If you manage the bucket policy for example for CRR or SRR already outside
the module, you need to be able to handle the policy without the module.

Signed-off-by: Arne-Kristian Hingst <arne@hingst.it>

Allow to disable the bucket policy

custom_origins is an object variable that can specify additional origins
apart from the default bucket. On top of that, to support "routing" the
ordered cache behavior was introduced.

Note that the implementation was based on CloudPosse's CloudFront module
Ref: https://github.com/cloudposse/terraform-aws-cloudfront-s3-cdn/

Adding Forwarded values to custom_origins using the default values from
variables.

Adding Custom origins and behaviors