Exposed the Date header on the outline api so clients can accurately compute times relative to the dates returned by the API; this was previously done with the course API (#26979)

Browser time is notoriously unreliable for this, especially for a Learner-facing countdown call-to-action based on the access expiration date. (REV-2126)

Using the Date header for this allows the client to make use of information that is already sent, does not require additional calls nor modifying the API, and could be generalized to more or all our APIs without modifying them.

Removed unused imports from lms/envs

AA-727

MICROBA-1039

[MICROBA-1100]
* Add CertificationGenerationCommandConfiguration model that will store the command arguments for the `cert_generation` mgmt command
* Add ability to add entries to the CertificationGenerationCommandConfiguration through Django admin
* Update mgmt command with ability to read arguments from the config model/database
* Fix failing test in `test_cert_generation.py`
* Add new test for missing `users` argument in `test_cert_generation.py`

MICROBA-1039

Co-authored-by: asadiqbal <aiqbal@edx.org>
Co-authored-by: asadiqbal08 <asad.iqbal@arbisoft.com>

Someone at edx was able to quickly send a few texts to himself using the tool.
Each text came from a different number and there was no message about the ability to unsubscribe or stop.
This could potentially be used to spam users as well as potentially result in charges to edX for high volume.

page url https://courses.edx.org/text-me-the-app
LEARNER-8286

MICROBA-1039

When considering whether a subsection is complete as an assignment,
skip any "hierarchy" types (sequential, vertical, etc) that don't
have children. If the user can't see the content, don't risk
marking it as complete.

AA-726

We heard about a bug where learners granted extensions would still
lose access to content if it was marked as "hidden after due date".
This was caused by the HiddenContentTransformer using the due date
from collection time (publish time) rather than the user date returned
from the edx-when DateOverrideTransformer.

A small subtletly of this PR is that Transformers with the
FilteringTransformerMixin are executed before those without it so
part of the fix was to make the HiddenContentTransformer not use the
FilteringTransformerMixin to ensure the DateOverrideTransformer had
run first.

Part 3/3 - Removing old collect code with merged due date

MICROBA-1039

We heard about a bug where learners granted extensions would still
lose access to content if it was marked as "hidden after due date".
This was caused by the HiddenContentTransformer using the due date
from collection time (publish time) rather than the user date returned
from the edx-when DateOverrideTransformer.

A small subtletly of these PRs is that Transformers with the
FilteringTransformerMixin are executed before those without it so
part of the fix was to make the HiddenContentTransformer not use the
FilteringTransformerMixin to ensure the DateOverrideTransformer had
run first.

Part 2/3 - Updating transform method + updating Read version

We heard about a bug where learners granted extensions would still
lose access to content if it was marked as "hidden after due date".
This was caused by the HiddenContentTransformer using the due date
from collection time (publish time) rather than the user date returned
from the edx-when DateOverrideTransformer.

A small subtletly of these PRs is that Transformers with the
FilteringTransformerMixin are executed before those without it so
part of the fix was to make the HiddenContentTransformer not use the
FilteringTransformerMixin to ensure the DateOverrideTransformer had
run first.

Part 1/3

The new WaffleFlag.is_enabled check in middleware increased query counts
for multiple tests.

MICROBA-1078

MICROBA-1039

Close https://github.com/openedx/build-test-release-wg/issues/10

Currently the registration endpoint has no rate limit. Added a new ratelimit
variable to support the change, it's value is set to 60/7d.

VAN-302

Removed tabindex="-1" from main element to fix accessibility issue
Description

Removed tabindex="-1"  from main
We had a strange issue where TalkBack wasn’t reading content in some xBlocks but was reading some others. I figured out that if you remove tabindex=-1 from <main>, TalkBack works as expected again. Tangentially, this breaks the old method of implementing SkipNav links. Further tangentially, the SkipNav links were already broken (or in this case redundant on mobile). @wittjeff  will file two separate issues after this one PR is merged — one  for a better way to implement SkipNav links for  Learning MFE, and one for a better / functional way to implement SkipNav links for Mobile.

How to reproduce
Go to [this unit](https://courses.edx.org/xblock/block-v1:W3Cx+WAI0.1x+3T2019+type@html+block@2eb3c86c479f44ba964f88ff0bfd9211) on mobile and turn on TalkBack. It will skip main content. For further information on testing go to [Jira Ticket](https://openedx.atlassian.net/browse/LEARNER-7858)

Fixes an issue where the button that linked to edX documentation for
course teams in Studio that displayed beside the logged-in user's username/
drop-down menu is gone. Regression from PR #26106

Ref: TNL-8138

* MST-682 Add external_user_key to the student profile CSV
This is a request from some Masters school partners. They would like to download the student enrolled list with the Masters external_user_key data referenced. This way, the schools can properly match the students enrolled in the course with the students enrolled through Masters enrollment system

For now only the discussion blocks were supported. If we had a custom XBlock that specified `completion_mode = XBlockCompletionMode.EXCLUDED`, then it could never be marked as completed on the course outline page, despite being marked as such inside the learning sequence.

This adds support for displaying completion on the course outline page, to remove the discrepancies between this view and the learning sequence. It also simplifies course outline page by reusing existing APIs for determining completion state and finding the "Resume block"'s target.

MICROBA-923

#27097 reverted the pylint amnesty change. After reverting the ubuntu20 deployment, now this can be deployed again.

* Updating Python Requirements

* fix proctoring test

Co-authored-by: Zulqarnain <muhammad.zulqarnain@arbisoft.com>