resource/aws_cloudfront_distribution: Adjust TypeSet and TypeList att…

…ributes for better difference handling

References:
* #7709
* #5526
* #4338
* #3842
* #3766
* #3256
* #1194
* #824
* #416

The usage of `TypeSet` for single container block attributes can cause unnecessary problems with Terraform's difference logic and makes plan output unnecessarily more difficult to read. Here we adjust these to `TypeList`.

Converted the following from `Type: schema.TypeSet` and `MaxItems: 1` to `Type: schema.TypeList`:

* `default_cache_behavior` configuration block
* `default_cache_behavior` configuration block `forwarded_values` configuration block
* `default_cache_behavior` configuration block `forwarded_values` configuration block `cookies` configuration block
* `logging_config` configuration block
* `origin` configuration block `custom_origin_config` configuration block
* `origin` configuration block `s3_origin_config` configuration block
* `ordered_cache_behavior` configuration block `forwarded_values` configuration block
* `ordered_cache_behavior` configuration block `forwarded_values` configuration block `cookies` configuration block
* `restrictions` configuration block
* `restrictions` configuration block `geo_restriction` configuration block
* `viewer_certificate` configuration block

The usage of `TypeList` for arguments where ordering does not matter causes unnecessary hassle for operators to match their configuration to the CloudFront API. Here we replace these with `TypeSet` to ignore ordering.

Converted the following from `Type: schema.TypeList` to `Type: schema.TypeSet`:

* `default_cache_behavior` configuration block `allowed_methods` argument
* `default_cache_behavior` configuration block `cached_methods` argument
* `origin` configuration block `custom_origin_config` configuration block `origin_ssl_protocols` argument
* `restrictions` configuration block `geo_restriction` configuration block `locations` argument

This change was verified with a live configuration outside the acceptance testing framework with Terraform 0.11 as effectively a no-op for the most common use case configurations that do not later reference these attributes.

```console
$ terraform apply
...
aws_cloudfront_distribution.test: Creating...
  active_trusted_signers.%:                                                                             "" => "<computed>"
  arn:                                                                                                  "" => "<computed>"
  caller_reference:                                                                                     "" => "<computed>"
  default_cache_behavior.#:                                                                             "0" => "1"
  default_cache_behavior.1848826977.allowed_methods.#:                                                  "0" => "7"
  default_cache_behavior.1848826977.allowed_methods.0:                                                  "" => "DELETE"
  default_cache_behavior.1848826977.allowed_methods.1:                                                  "" => "GET"
  default_cache_behavior.1848826977.allowed_methods.2:                                                  "" => "HEAD"
  default_cache_behavior.1848826977.allowed_methods.3:                                                  "" => "OPTIONS"
  default_cache_behavior.1848826977.allowed_methods.4:                                                  "" => "PATCH"
  default_cache_behavior.1848826977.allowed_methods.5:                                                  "" => "POST"
  default_cache_behavior.1848826977.allowed_methods.6:                                                  "" => "PUT"
  default_cache_behavior.1848826977.cached_methods.#:                                                   "0" => "2"
  default_cache_behavior.1848826977.cached_methods.0:                                                   "" => "GET"
  default_cache_behavior.1848826977.cached_methods.1:                                                   "" => "HEAD"
  default_cache_behavior.1848826977.compress:                                                           "" => "false"
  default_cache_behavior.1848826977.default_ttl:                                                        "" => "100"
  default_cache_behavior.1848826977.field_level_encryption_id:                                          "" => ""
  default_cache_behavior.1848826977.forwarded_values.#:                                                 "0" => "1"
  default_cache_behavior.1848826977.forwarded_values.2510654351.cookies.#:                              "0" => "1"
  default_cache_behavior.1848826977.forwarded_values.2510654351.cookies.1870923232.forward:             "" => "all"
  default_cache_behavior.1848826977.forwarded_values.2510654351.cookies.1870923232.whitelisted_names.#: "0" => "0"
  default_cache_behavior.1848826977.forwarded_values.2510654351.headers.#:                              "0" => "0"
  default_cache_behavior.1848826977.forwarded_values.2510654351.query_string:                           "" => "false"
  default_cache_behavior.1848826977.forwarded_values.2510654351.query_string_cache_keys.#:              "0" => "0"
  default_cache_behavior.1848826977.lambda_function_association.#:                                      "0" => "0"
  default_cache_behavior.1848826977.max_ttl:                                                            "" => "100"
  default_cache_behavior.1848826977.min_ttl:                                                            "" => "100"
  default_cache_behavior.1848826977.smooth_streaming:                                                   "" => "true"
  default_cache_behavior.1848826977.target_origin_id:                                                   "" => "myCustomOrigin"
  default_cache_behavior.1848826977.trusted_signers.#:                                                  "0" => "0"
  default_cache_behavior.1848826977.viewer_protocol_policy:                                             "" => "allow-all"
  domain_name:                                                                                          "" => "<computed>"
  enabled:                                                                                              "" => "true"
  etag:                                                                                                 "" => "<computed>"
  hosted_zone_id:                                                                                       "" => "<computed>"
  http_version:                                                                                         "" => "http2"
  in_progress_validation_batches:                                                                       "" => "<computed>"
  is_ipv6_enabled:                                                                                      "" => "false"
  last_modified_time:                                                                                   "" => "<computed>"
  ordered_cache_behavior.#:                                                                             "0" => "2"
  ordered_cache_behavior.0.allowed_methods.#:                                                           "0" => "7"
  ordered_cache_behavior.0.allowed_methods.1012961568:                                                  "" => "POST"
  ordered_cache_behavior.0.allowed_methods.1040875975:                                                  "" => "GET"
  ordered_cache_behavior.0.allowed_methods.1445840968:                                                  "" => "HEAD"
  ordered_cache_behavior.0.allowed_methods.1741119464:                                                  "" => "PATCH"
  ordered_cache_behavior.0.allowed_methods.348445828:                                                   "" => "DELETE"
  ordered_cache_behavior.0.allowed_methods.3982006612:                                                  "" => "OPTIONS"
  ordered_cache_behavior.0.allowed_methods.4024585617:                                                  "" => "PUT"
  ordered_cache_behavior.0.cached_methods.#:                                                            "0" => "2"
  ordered_cache_behavior.0.cached_methods.1040875975:                                                   "" => "GET"
  ordered_cache_behavior.0.cached_methods.1445840968:                                                   "" => "HEAD"
  ordered_cache_behavior.0.compress:                                                                    "" => "false"
  ordered_cache_behavior.0.default_ttl:                                                                 "" => "50"
  ordered_cache_behavior.0.forwarded_values.#:                                                          "0" => "1"
  ordered_cache_behavior.0.forwarded_values.2555876073.cookies.#:                                       "0" => "1"
  ordered_cache_behavior.0.forwarded_values.2555876073.cookies.2625240281.forward:                      "" => "none"
  ordered_cache_behavior.0.forwarded_values.2555876073.cookies.2625240281.whitelisted_names.#:          "0" => "0"
  ordered_cache_behavior.0.forwarded_values.2555876073.headers.#:                                       "0" => "0"
  ordered_cache_behavior.0.forwarded_values.2555876073.query_string:                                    "" => "true"
  ordered_cache_behavior.0.forwarded_values.2555876073.query_string_cache_keys.#:                       "0" => "0"
  ordered_cache_behavior.0.max_ttl:                                                                     "" => "50"
  ordered_cache_behavior.0.min_ttl:                                                                     "" => "50"
  ordered_cache_behavior.0.path_pattern:                                                                "" => "images1/*.jpg"
  ordered_cache_behavior.0.target_origin_id:                                                            "" => "myCustomOrigin"
  ordered_cache_behavior.0.viewer_protocol_policy:                                                      "" => "allow-all"
  ordered_cache_behavior.1.allowed_methods.#:                                                           "0" => "7"
  ordered_cache_behavior.1.allowed_methods.1012961568:                                                  "" => "POST"
  ordered_cache_behavior.1.allowed_methods.1040875975:                                                  "" => "GET"
  ordered_cache_behavior.1.allowed_methods.1445840968:                                                  "" => "HEAD"
  ordered_cache_behavior.1.allowed_methods.1741119464:                                                  "" => "PATCH"
  ordered_cache_behavior.1.allowed_methods.348445828:                                                   "" => "DELETE"
  ordered_cache_behavior.1.allowed_methods.3982006612:                                                  "" => "OPTIONS"
  ordered_cache_behavior.1.allowed_methods.4024585617:                                                  "" => "PUT"
  ordered_cache_behavior.1.cached_methods.#:                                                            "0" => "2"
  ordered_cache_behavior.1.cached_methods.1040875975:                                                   "" => "GET"
  ordered_cache_behavior.1.cached_methods.1445840968:                                                   "" => "HEAD"
  ordered_cache_behavior.1.compress:                                                                    "" => "false"
  ordered_cache_behavior.1.default_ttl:                                                                 "" => "51"
  ordered_cache_behavior.1.forwarded_values.#:                                                          "0" => "1"
  ordered_cache_behavior.1.forwarded_values.2555876073.cookies.#:                                       "0" => "1"
  ordered_cache_behavior.1.forwarded_values.2555876073.cookies.2625240281.forward:                      "" => "none"
  ordered_cache_behavior.1.forwarded_values.2555876073.cookies.2625240281.whitelisted_names.#:          "0" => "0"
  ordered_cache_behavior.1.forwarded_values.2555876073.headers.#:                                       "0" => "0"
  ordered_cache_behavior.1.forwarded_values.2555876073.query_string:                                    "" => "true"
  ordered_cache_behavior.1.forwarded_values.2555876073.query_string_cache_keys.#:                       "0" => "0"
  ordered_cache_behavior.1.max_ttl:                                                                     "" => "51"
  ordered_cache_behavior.1.min_ttl:                                                                     "" => "51"
  ordered_cache_behavior.1.path_pattern:                                                                "" => "images2/*.jpg"
  ordered_cache_behavior.1.target_origin_id:                                                            "" => "myCustomOrigin"
  ordered_cache_behavior.1.viewer_protocol_policy:                                                      "" => "allow-all"
  origin.#:                                                                                             "0" => "1"
  origin.1857972443.custom_header.#:                                                                    "0" => "0"
  origin.1857972443.custom_origin_config.#:                                                             "0" => "1"
  origin.1857972443.custom_origin_config.3832794885.http_port:                                          "" => "80"
  origin.1857972443.custom_origin_config.3832794885.https_port:                                         "" => "443"
  origin.1857972443.custom_origin_config.3832794885.origin_keepalive_timeout:                           "" => "5"
  origin.1857972443.custom_origin_config.3832794885.origin_protocol_policy:                             "" => "http-only"
  origin.1857972443.custom_origin_config.3832794885.origin_read_timeout:                                "" => "30"
  origin.1857972443.custom_origin_config.3832794885.origin_ssl_protocols.#:                             "0" => "2"
  origin.1857972443.custom_origin_config.3832794885.origin_ssl_protocols.0:                             "" => "SSLv3"
  origin.1857972443.custom_origin_config.3832794885.origin_ssl_protocols.1:                             "" => "TLSv1"
  origin.1857972443.domain_name:                                                                        "" => "www.example.com"
  origin.1857972443.origin_id:                                                                          "" => "myCustomOrigin"
  origin.1857972443.origin_path:                                                                        "" => ""
  origin.1857972443.s3_origin_config.#:                                                                 "0" => "0"
  price_class:                                                                                          "" => "PriceClass_All"
  restrictions.#:                                                                                       "0" => "1"
  restrictions.811065190.geo_restriction.#:                                                             "0" => "1"
  restrictions.811065190.geo_restriction.1303118592.locations.#:                                        "0" => "4"
  restrictions.811065190.geo_restriction.1303118592.locations.0:                                        "" => "US"
  restrictions.811065190.geo_restriction.1303118592.locations.1:                                        "" => "CA"
  restrictions.811065190.geo_restriction.1303118592.locations.2:                                        "" => "GB"
  restrictions.811065190.geo_restriction.1303118592.locations.3:                                        "" => "DE"
  restrictions.811065190.geo_restriction.1303118592.restriction_type:                                   "" => "whitelist"
  retain_on_delete:                                                                                     "" => "false"
  status:                                                                                               "" => "<computed>"
  viewer_certificate.#:                                                                                 "0" => "1"
  viewer_certificate.69840937.acm_certificate_arn:                                                      "" => ""
  viewer_certificate.69840937.cloudfront_default_certificate:                                           "" => "true"
  viewer_certificate.69840937.iam_certificate_id:                                                       "" => ""
  viewer_certificate.69840937.minimum_protocol_version:                                                 "" => "TLSv1"
  viewer_certificate.69840937.ssl_support_method:                                                       "" => ""
aws_cloudfront_distribution.test: Creation complete after 0s (ID: E3K1GJF3SSNJRN)

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

$ cp ~/go/bin/terraform-provider-aws .terraform/plugins/darwin_amd64/terraform-provider-aws_v1.60.0_x4; terraform init # this binary is an updated Terraform AWS Provider built with these changes

$ terraform apply # Here we see no state migration required
aws_cloudfront_distribution.test: Refreshing state... (ID: E3K1GJF3SSNJRN)

Apply complete! Resources: 0 added, 0 changed, 0 destroyed.

$ terraform state show aws_cloudfront_distribution.test # Here we see a successful state refresh with the new layout
id                                                                        = E3K1GJF3SSNJRN
active_trusted_signers.%                                                  = 2
active_trusted_signers.enabled                                            = false
active_trusted_signers.items.#                                            = 0
aliases.#                                                                 = 0
arn                                                                       = arn:aws:cloudfront::187416307283:distribution/E3K1GJF3SSNJRN
caller_reference                                                          = 2019-02-25T14:51:42.674464-05:00
custom_error_response.#                                                   = 0
default_cache_behavior.#                                                  = 1
default_cache_behavior.0.allowed_methods.#                                = 7
default_cache_behavior.0.allowed_methods.1012961568                       = POST
default_cache_behavior.0.allowed_methods.1040875975                       = GET
default_cache_behavior.0.allowed_methods.1445840968                       = HEAD
default_cache_behavior.0.allowed_methods.1741119464                       = PATCH
default_cache_behavior.0.allowed_methods.348445828                        = DELETE
default_cache_behavior.0.allowed_methods.3982006612                       = OPTIONS
default_cache_behavior.0.allowed_methods.4024585617                       = PUT
default_cache_behavior.0.cached_methods.#                                 = 2
default_cache_behavior.0.cached_methods.1040875975                        = GET
default_cache_behavior.0.cached_methods.1445840968                        = HEAD
default_cache_behavior.0.compress                                         = false
default_cache_behavior.0.default_ttl                                      = 100
default_cache_behavior.0.field_level_encryption_id                        =
default_cache_behavior.0.forwarded_values.#                               = 1
default_cache_behavior.0.forwarded_values.0.cookies.#                     = 1
default_cache_behavior.0.forwarded_values.0.cookies.0.forward             = all
default_cache_behavior.0.forwarded_values.0.cookies.0.whitelisted_names.# = 0
default_cache_behavior.0.forwarded_values.0.headers.#                     = 0
default_cache_behavior.0.forwarded_values.0.query_string                  = false
default_cache_behavior.0.forwarded_values.0.query_string_cache_keys.#     = 0
default_cache_behavior.0.lambda_function_association.#                    = 0
default_cache_behavior.0.max_ttl                                          = 100
default_cache_behavior.0.min_ttl                                          = 100
default_cache_behavior.0.smooth_streaming                                 = true
default_cache_behavior.0.target_origin_id                                 = myCustomOrigin
default_cache_behavior.0.trusted_signers.#                                = 0
default_cache_behavior.0.viewer_protocol_policy                           = allow-all
default_root_object                                                       =
domain_name                                                               = dot6h04nf0cmx.cloudfront.net
enabled                                                                   = true
etag                                                                      = E33ZADXZHBHVXT
hosted_zone_id                                                            = Z2FDTNDATAQYW2
http_version                                                              = http2
in_progress_validation_batches                                            = 0
is_ipv6_enabled                                                           = false
last_modified_time                                                        = 2019-02-26 02:22:40.558 +0000 UTC
logging_config.#                                                          = 0
ordered_cache_behavior.#                                                  = 2
ordered_cache_behavior.0.allowed_methods.#                                = 7
ordered_cache_behavior.0.allowed_methods.1012961568                       = POST
ordered_cache_behavior.0.allowed_methods.1040875975                       = GET
ordered_cache_behavior.0.allowed_methods.1445840968                       = HEAD
ordered_cache_behavior.0.allowed_methods.1741119464                       = PATCH
ordered_cache_behavior.0.allowed_methods.348445828                        = DELETE
ordered_cache_behavior.0.allowed_methods.3982006612                       = OPTIONS
ordered_cache_behavior.0.allowed_methods.4024585617                       = PUT
ordered_cache_behavior.0.cached_methods.#                                 = 2
ordered_cache_behavior.0.cached_methods.1040875975                        = GET
ordered_cache_behavior.0.cached_methods.1445840968                        = HEAD
ordered_cache_behavior.0.compress                                         = false
ordered_cache_behavior.0.default_ttl                                      = 50
ordered_cache_behavior.0.field_level_encryption_id                        =
ordered_cache_behavior.0.forwarded_values.#                               = 1
ordered_cache_behavior.0.forwarded_values.0.cookies.#                     = 1
ordered_cache_behavior.0.forwarded_values.0.cookies.0.forward             = none
ordered_cache_behavior.0.forwarded_values.0.cookies.0.whitelisted_names.# = 0
ordered_cache_behavior.0.forwarded_values.0.headers.#                     = 0
ordered_cache_behavior.0.forwarded_values.0.query_string                  = true
ordered_cache_behavior.0.forwarded_values.0.query_string_cache_keys.#     = 0
ordered_cache_behavior.0.lambda_function_association.#                    = 0
ordered_cache_behavior.0.max_ttl                                          = 50
ordered_cache_behavior.0.min_ttl                                          = 50
ordered_cache_behavior.0.path_pattern                                     = images1/*.jpg
ordered_cache_behavior.0.smooth_streaming                                 = false
ordered_cache_behavior.0.target_origin_id                                 = myCustomOrigin
ordered_cache_behavior.0.trusted_signers.#                                = 0
ordered_cache_behavior.0.viewer_protocol_policy                           = allow-all
ordered_cache_behavior.1.allowed_methods.#                                = 7
ordered_cache_behavior.1.allowed_methods.1012961568                       = POST
ordered_cache_behavior.1.allowed_methods.1040875975                       = GET
ordered_cache_behavior.1.allowed_methods.1445840968                       = HEAD
ordered_cache_behavior.1.allowed_methods.1741119464                       = PATCH
ordered_cache_behavior.1.allowed_methods.348445828                        = DELETE
ordered_cache_behavior.1.allowed_methods.3982006612                       = OPTIONS
ordered_cache_behavior.1.allowed_methods.4024585617                       = PUT
ordered_cache_behavior.1.cached_methods.#                                 = 2
ordered_cache_behavior.1.cached_methods.1040875975                        = GET
ordered_cache_behavior.1.cached_methods.1445840968                        = HEAD
ordered_cache_behavior.1.compress                                         = false
ordered_cache_behavior.1.default_ttl                                      = 51
ordered_cache_behavior.1.field_level_encryption_id                        =
ordered_cache_behavior.1.forwarded_values.#                               = 1
ordered_cache_behavior.1.forwarded_values.0.cookies.#                     = 1
ordered_cache_behavior.1.forwarded_values.0.cookies.0.forward             = none
ordered_cache_behavior.1.forwarded_values.0.cookies.0.whitelisted_names.# = 0
ordered_cache_behavior.1.forwarded_values.0.headers.#                     = 0
ordered_cache_behavior.1.forwarded_values.0.query_string                  = true
ordered_cache_behavior.1.forwarded_values.0.query_string_cache_keys.#     = 0
ordered_cache_behavior.1.lambda_function_association.#                    = 0
ordered_cache_behavior.1.max_ttl                                          = 51
ordered_cache_behavior.1.min_ttl                                          = 51
ordered_cache_behavior.1.path_pattern                                     = images2/*.jpg
ordered_cache_behavior.1.smooth_streaming                                 = false
ordered_cache_behavior.1.target_origin_id                                 = myCustomOrigin
ordered_cache_behavior.1.trusted_signers.#                                = 0
ordered_cache_behavior.1.viewer_protocol_policy                           = allow-all
origin.#                                                                  = 1
origin.1857972443.custom_header.#                                         = 0
origin.1857972443.custom_origin_config.#                                  = 1
origin.1857972443.custom_origin_config.0.http_port                        = 80
origin.1857972443.custom_origin_config.0.https_port                       = 443
origin.1857972443.custom_origin_config.0.origin_keepalive_timeout         = 5
origin.1857972443.custom_origin_config.0.origin_protocol_policy           = http-only
origin.1857972443.custom_origin_config.0.origin_read_timeout              = 30
origin.1857972443.custom_origin_config.0.origin_ssl_protocols.#           = 2
origin.1857972443.custom_origin_config.0.origin_ssl_protocols.1162609714  = TLSv1
origin.1857972443.custom_origin_config.0.origin_ssl_protocols.2159350162  = SSLv3
origin.1857972443.domain_name                                             = www.example.com
origin.1857972443.origin_id                                               = myCustomOrigin
origin.1857972443.origin_path                                             =
origin.1857972443.s3_origin_config.#                                      = 0
price_class                                                               = PriceClass_All
restrictions.#                                                            = 1
restrictions.0.geo_restriction.#                                          = 1
restrictions.0.geo_restriction.0.locations.#                              = 4
restrictions.0.geo_restriction.0.locations.3034033770                     = DE
restrictions.0.geo_restriction.0.locations.3047936762                     = US
restrictions.0.geo_restriction.0.locations.3589570027                     = CA
restrictions.0.geo_restriction.0.locations.4191192820                     = GB
restrictions.0.geo_restriction.0.restriction_type                         = whitelist
retain_on_delete                                                          = false
status                                                                    = Deployed
tags.%                                                                    = 0
viewer_certificate.#                                                      = 1
viewer_certificate.0.acm_certificate_arn                                  =
viewer_certificate.0.cloudfront_default_certificate                       = true
viewer_certificate.0.iam_certificate_id                                   =
viewer_certificate.0.minimum_protocol_version                             = TLSv1
viewer_certificate.0.ssl_support_method                                   =
web_acl_id                                                                =
```

Output from acceptance testing:

```
--- PASS: TestAccAWSCloudFrontDistribution_Origin_EmptyOriginID (1.04s)
--- PASS: TestAccAWSCloudFrontDistribution_Origin_EmptyDomainName (1.12s)
--- PASS: TestAccAWSCloudFrontDistribution_orderedCacheBehavior (1082.43s)
--- PASS: TestAccAWSCloudFrontDistribution_HTTP11Config (1082.47s)
--- PASS: TestAccAWSCloudFrontDistribution_noCustomErrorResponseConfig (1083.16s)
--- PASS: TestAccAWSCloudFrontDistribution_noOptionalItemsConfig (1083.56s)
--- PASS: TestAccAWSCloudFrontDistribution_S3OriginWithTags (1084.20s)
--- PASS: TestAccAWSCloudFrontDistribution_IsIPV6EnabledConfig (1089.11s)
--- PASS: TestAccAWSCloudFrontDistribution_S3Origin (1090.38s)
--- PASS: TestAccAWSCloudFrontDistribution_customOrigin (1092.54s)
--- PASS: TestAccAWSCloudFrontDistribution_multiOrigin (1093.67s)
```