feat: add features dict to EnterpriseCustomerViewSet

[adamstankiewicz]

Ticket: https://2u-internal.atlassian.net/browse/ENT-7713

Adds support for exposing Waffle-based feature flags onto the default paginated response in the EnterpriseCustomerViewSet such that micro-frontends already calling API endpoint(s) from this viewset have access to the Waffle-based feature flags without introducing new API integrations.

See ADR (preview) for more details around this approach.

Example API response with enterprise_features object included:

{
    "next": null,
    "previous": null,
    "count": 1,
    "num_pages": 1,
    "current_page": 1,
    "start": 0,
    "results": [
        {
            "uuid": "a067aacd-667d-4bd6-81e2-e332ef5ca1cd",
            "name": "Test Enterprise",
            "slug": "test-enterprise",
            "active": true,
            // ...
        }
    ],
    "enterprise_features": {
        "top_down_assignment_real_time_lcm": true
    }
}

Merge checklist:

• Any new requirements are in the right place (do not manually modify the requirements/*.txt files)
  • base.in if needed in production but edx-platform doesn't install it
  • test-master.in if edx-platform pins it, with a matching version
  • make upgrade && make requirements have been run to regenerate requirements
• make static has been run to update webpack bundling if any static content was updated
• ./manage.py makemigrations has been run
  • Checkout the Database Migration Confluence page for helpful tips on creating migrations.
  • Note: This must be run if you modified any models.
    • It may or may not make a migration depending on exactly what you modified, but it should still be run.
  • This should be run from either a venv with all the lms/edx-enterprise requirements installed or if you checked out edx-enterprise into the src directory used by lms, you can run this command through an lms shell.
    • It would be ./manage.py lms makemigrations in the shell.
• Version bumped
• Changelog record added
• Translations updated (see docs/internationalization.rst but also this isn't blocking for merge atm)

Post merge:

• Tag pushed and a new version released
  • Note: Assets will be added automatically. You just need to provide a tag (should match your version number) and title and description.
• After versioned build finishes in GitHub Actions, verify version has been pushed to PyPI
  • Each step in the release build has a condition flag that checks if the rest of the steps are done and if so will deploy to PyPi.
    (so basically once your build finishes, after maybe a minute you should see the new version in PyPi automatically (on refresh))
• PR created in edx-platform to upgrade dependencies (including edx-enterprise)
  • This must be done after the version is visible in PyPi as make upgrade in edx-platform will look for the latest version in PyPi.
  • Note: the edx-enterprise constraint in edx-platform must also be bumped to the latest version in PyPi.

[pwnage101]

I don't understand why num_pages, current_page, and start were all net additions. Didn't you just extend DefaultPagination? Not a blocker.

[iloveagent57]

The default pagination was probably the vanilla DRF page-number paginator set via settings file. Adam's new paginator extends the edX-DRF default paginator: https://github.com/openedx/edx-drf-extensions/blob/master/edx_rest_framework_extensions/paginators.py

[pwnage101]

Recommendation: add a function to toggles.py to serialize this dictionary so that adding a new feature flag is limited to just updating one file.

[adamstankiewicz]

Great suggestion! I will update this PR after afternoon meetings.