User self-registration

[fmigneault]

Features / Changes

• Changed UserStatuses.WebhookErrorStatus = 0 to UserStatuses.WebhookError = 2 to provide further
  functionalities. Migration script applies this change to existing User entries.
• Changed the returned status value by the API routes to use the string name representation instead of the integer.
• Changed status search query handling of GET /users path for improved search and filtering capabilities.
• Add new UserStatuses.Pending = 4 value that can be queried by administrators.
• Add UserPending object with corresponding table for pending approval by an administrator for some new
  self-registered user. Migration script creates the table with expected fields.
• Add new requests under /register/users and /ui/register/users endpoints for user account self-registration.
• Add UI view to display pending user registration details.
• Add UI icon to indicate when a listed user is pending registration approval or email validation.
• Disable user email self-update (when not administrator) both on the API and UI side
  whenever MAGPIE_USER_REGISTRATION_ENABLED was activated to avoid losing the confirmation of the original email.
• Add configuration setting MAGPIE_USER_REGISTRATION_ENABLED to control whether user account self-registration
  feature should be employed.
  With it comes multiple other MAGPIE_USER_REGISTRATION_<...> settings to customize notification emails.
• Add multiple MAGPIE_SMTP_<...> configuration settings to control connections to notification email SMTP server.
• Add empty_missing flag to get_constant utility to allow validation against existing environment variables or
  settings that should be considered as invalid when resolved value is an empty string.
• Add missing format for applicable url and email elements in the OpenAPI specification.
• Add better logging options control in CLI operations.
• Add new CLI helper send_email to test various email template generation and SMTP configurations to send emails.
• Replace -d option of register_providers CLI operation (previously used to select database mode)
  by --db to avoid conflict with logging flags.
• Replace -d and -l options of batch_update_users CLI operation respectively by -D and -L
  to avoid conflict with logging flags.

Bug Fixes

• Explicitly disallow duplicate email entries, both with pre-validation and literal database values.
  Note that any duplicate email will be raised an migration script will fail. Manual cleanup of the undesired entry
  will be required, as Magpie will not be able to assume which one corresponds to the valid user to preserve.

• Add ziggurat_foundations extensions for Pyramid directly in the code during application setup such that an INI
  configuration file that omits them from pyramid.include won't cause Magpie to break.

Other references

Implements feature DAC-117

[codecov-commenter]

Codecov Report

Merging #435 (e97d68c) into master (1167b2c) will increase coverage by 0.67%.
The diff coverage is 77.99%.

@@            Coverage Diff             @@
##           master     #435      +/-   ##
==========================================
+ Coverage   78.40%   79.07%   +0.67%     
==========================================
  Files          66       70       +4     
  Lines        8019     8779     +760     
  Branches     1080     1201     +121     
==========================================
+ Hits         6287     6942     +655     
- Misses       1496     1558      +62     
- Partials      236      279      +43     

Impacted Files	Coverage Δ
magpie/permissions.py	92.46% <ø> (+0.79%)	⬆️
magpie/services.py	80.25% <ø> (ø)
magpie/ui/management/views.py	47.32% <58.53%> (+0.46%)	⬆️
magpie/cli/send_email.py	60.71% <60.71%> (ø)
magpie/ui/utils.py	66.45% <61.03%> (-6.89%)	⬇️
magpie/api/notifications.py	64.28% <64.28%> (ø)
magpie/cli/register_defaults.py	65.17% <66.66%> (-0.28%)	⬇️
magpie/cli/sync_resources.py	32.06% <66.66%> (+0.19%)	⬆️
magpie/cli/utils.py	69.23% <69.23%> (ø)
magpie/api/management/user/user_utils.py	96.02% <70.58%> (-1.34%)	⬇️
... and 32 more

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[fmigneault]

@ChaamC
Tagging you as some of the files/configs needed for T&C feature are added here.

[dbyrns]

Review in progress 5/74

[dbyrns]

Review in progress 19/74

[dbyrns]

Review completed. Great job!

[dbyrns]

Still good for me