[MICROBA-1466]

Credentials needs the course certificate date override data in a
slightly different format than we were passing it before. Fix!

When sending a GeneratedCertificate to Credentials, send the associated
CertificateDateOverride (if there is one), or else None. This
will be triggered after any save of a GeneratedCertificate, and after
any save or deletion of a single CertificateDateOverride.

Credentials will eventually store its own copy of this date override, or
edit or remove exiting date overrides.

* refactor: Merge the openedx certs app with lms one

Move the certs API from openedx into the lms certificates app.
Functionally, this is a no-op. Cleanup will happen in a subsequent
commit. This is simply a move.

* [fix] Fix certificate available date sync

We were syncing the course available date to every course in
credentials. Since credentials doesn't understand "self-paced" courses,
or course end behaviors, some certificates were time gated incorrectly.
This check make sure to check if the course is not self-paced, and has a
CDB of 'end' before syncing the CA date.

Program tasks got moved from tasks.v1.tasks.py to just tasks.py, but
the mapping was never updated.

* [feat] Management command to populate credentials availability date

This is a command to populate the new CredentialsCertificate model's
available_date for every existing course_run.

* [feat] calling course certificates api from LMS

Now that CourseCertificates in credentials have a field for the
available_date, we need to make sure we are always updating that field
when it changes in studio. This PR adds a call to a new Credentials API
that will update the field each time the date change signal fires.

[MICROBA-1164]
* cast `course_key` as a string when scheduling the `revoke_program_certificates` task
* Update existing unit tests
* Move test utility method in test_tasks.py out from the middle of the test cases
* Fix spelling in test function name

Because the available date update to the CourseOverview happens inside a
view's signal and we have atomic requests on, the read that was
happening inside the task happened *before* the write was commited to
the database. To avoid the unknown bugs that would come from disabling
atomic transactions for that view (since it's large), this passes the
date we want down through the signals and tasks so we can skip the DB
read at the end.

I believe there to be a race condition here that only manifests in a
non-devstack environment. Adding some logging to better diagnose.

COURSE_CERT_DATE_CHANGE was being called before saving the new data in
the course overview. The listeners were expecting to pull the data out
of the course overview, and thus were only right about half the time.
This moves the signal to trigger after the course publish signals are
handled.

The logging text was duplicated from a different function

In order to better alert off of tasks that failed after maximum retries,
this makes the the error for each task consistent with itself.

* Update celery routing

- Used routing function instead of class
- Move task queues dictionary to Django settings
- Removed routing_key parameter
- Refactored routing for singleton celery instantiation

Co-authored-by: Awais Qureshi <awais.qureshi@arbisoft.com>

ARCHBOM-1260

Co-authored-by: Tim McCormack <tmccormack@edx.org>

This reverts commit db4c3b12.

This reverts commit c1fe3c3a.

* Generate common/djangoapps import shims for LMS
* Generate common/djangoapps import shims for Studio
* Stop appending project root to sys.path
* Stop appending common/djangoapps to sys.path
* Import from common.djangoapps.course_action_state instead of course_action_state
* Import from common.djangoapps.course_modes instead of course_modes
* Import from common.djangoapps.database_fixups instead of database_fixups
* Import from common.djangoapps.edxmako instead of edxmako
* Import from common.djangoapps.entitlements instead of entitlements
* Import from common.djangoapps.pipline_mako instead of pipeline_mako
* Import from common.djangoapps.static_replace instead of static_replace
* Import from common.djangoapps.student instead of student
* Import from common.djangoapps.terrain instead of terrain
* Import from common.djangoapps.third_party_auth instead of third_party_auth
* Import from common.djangoapps.track instead of track
* Import from common.djangoapps.util instead of util
* Import from common.djangoapps.xblock_django instead of xblock_django
* Add empty common/djangoapps/__init__.py to fix pytest collection
* Fix pylint formatting violations
* Exclude import_shims/ directory tree from linting

This reverts commit 39a22734.

* Revert "Revert "Update routing config"

* Removed settings from lms/celery.py and cms/celery.py

* Moved settings import from top-level to function's scopes

Co-authored-by: Soban Javed <iamsobanjaved@gmail.com>

- Used routing function istead of class
- Move task queues to Djano settings
- Removed routing_key parameter

[MICROBA-676]

Upon invalidating course certificate, revoke related program certificates
as well.

PROD-1271

This will remove imports from __future__ that are no longer needed.

https://docs.python.org/3.5/library/2to3.html#2to3fixer-future

BackPopulate Program Credentials job performs data for all the programs
and for all the available learners which takes a lot of time.
Adding in custom arguments will help run this job for specific learners
and specific programs.

* INCR-239: Run python-modernize and isort on openedx/core/djangoapps/programs [tests, tasks]

* INCR-239: Grouped six package and represent unused variables with _

JIRA:EDUCATOR-4022