Instead of hard-coding the "Learn More" and potentially other links for course
apps in the course authoring  MFEs this change loads those URLs from the
django settings as part of each individual course app.

* fix: add code owner mapping for edx-name-affirmation

Enables edx_name_affirmation views to have a code owner.

fix: allow importing courses into Studio with empty libraries

If a content library xblock does not specify a library id, we
previously would error out when importing, due to some cleanup
code that wasn't accounting for this case.

chore: upgrade edx-name-affirmation to 0.3.1

Sanitizes Markdown that goes back and forth between the server and
client side, to strip out data: links, so that they cannot be abused.
There is no present vulnerability to this issue–modern browsers disallow
data links in the first place, and we already filter this out in both
client-side code as well as the HTML generated in the REST API (it's run
through bleach). But we're adding this anyway, to further reduce the
odds that some client-side mistake could cause a vulnerability. This is
part of TNL-8589.

maint: bumping enterprise version to 3.27.14

fix: Update mode in course certificate when marking cert as invalidated, not verified or not passing (#28330)

MICROBA-1410

Some providers need special considerations when being set up so should only be
configured by people with global staff privileges. This adds an
admin_only_config flag to such providers (only YellowDig for now).

LOGIN_REDIRECT_WHITELIST has been used to filter redirect-url while processing logout requests but its configurations were not picked through environment files like lms.yml or studio.yml. This PR fixes that bug.

* chore: Removed python_2_unicode_compatible decorator.

Mergeback PR from private to public.

ENT-4789

commits
=======
- fix(ci): move github workflow to correct location

feat: Add CertificateDateOverride model

Add a new model (and corresponding migration) to the certificates
app in the LMS: CertificateDateOverride. The model will eventually be
used to allow course teams / support to override the "Issued On" date
for a given course certificate.

I used Github's UI to create this from the template (which I _never_ do,
instead opting for the CLI) and some how this ended up in the project
root, instead of in the .github/workflows directory. 

Back to the command line for me...

chore: upgrade edx-name-affirmation to 0.3.0

refactor!: Remove `generate_example_certificates` and update Instructor Dashboard with updated messaging.

refactor!: Remove `generate_example_certificates` and update Instructor Dashboard with updated messaging.

[MICROBA-1087]
[DEPR-155]

* Remove `generate_example_certificates` functionality
* Adjust Instructor dashboard slightly to prevent people from clicking the `Generate Example Certificates` button, remove form/code that called the `generate_example_certificates` endpoint.

fix: don't recreate course overview images every request

MICROBA-678

maint: bumping enterprise version to 3.27.12

This reduces database churn and helps avoid locks.

fix: discussion xss fix

fix: wrong start date is displayed in susbection modal

feat: reimagine certificate display settings

The course settings `certificate_available_date` (CAD) and
`certificates_display_behavior` (CDB) were previously
acting indedependantly of one another. They now work in
tandem. This change:
- limits CDB to a dropdown
- removes "early_with_info" and adds "end_with_date"
- only takes CAD into account if "end_with_date" is selected
- Moves CDB to the main course schedule settings page
- updates CourseOverview model and CourseDetails objects to
validate these fields and choose sane defaults if they aren't
expected values

This work was previously done in bd9e7dd (complete with bugs), so this
version is toggleable via the ENABLE_V2_CERT_DISPLAY_SETTINGS setting

Formerly, bulk management was enabled by sending feature feature
toggle to Gradebook which also checked for the presence of a 
master's track to enable the feature. This default enables for all
courses with a master's track and also allows selective enabling 
for courses with the feature flag.

MICROBA-1410

chore: Removed constraint on django-countries

chore: Django3 has removed python_2_unicode_compatible.