Removed unused imports from openedx/core/djangoapps/{api_admin, catalog, ccxcon, certificates}

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.

* lint amnesty in openedx apps

* 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

Specifically, pass the MFE the audit access expiration date and
let it know when the upgrade deadline has passed, by not passing
any verified mode information along.

Learner who have already earned PDF honor certificates in old courses
are unable to see the certificate links on dashboard and course progress
pages since `course.cert_html_view_enabled` is deprecated and default to
True for all courses.

PROD-60

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

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

* modernize openedx/core/djangoapps/certificates
openedx/core/djangoapps/commerce
openedx/core/djangoapps/common_initialization
openedx/core/djangoapps/config_model_utils

* rewmove unused import

If we have a future available_date, send that to Credentials rather
than sending the modified date.

LEARNER-5995

EDUCATOR-2017.

White listed certificates should appear on the progress page
even if the user has not passed the course
LEARNER-3546

for EDUCATOR-1313