Does 3 things:
(1) Use django for modulestore tests
(2) Use normal LMS settings for modulestore tests instead of openedx/tests/settings.py
(3) Simplify some TestCase subclasses by converting them to use ModuleStoreTestCase
Details and rationale:
(1) Currently parts of the modulestore test suite are designed to run "without django", although there is still a lot of django functionality imported at times, and many of the tests do in fact use django. But for the upcoming PR #27565 (moving split's course indexes from MongoDB to MySQL), we will need to always have Django enabled. So this commit paves the way for that change.
(2) The previous tests that did use Django used a special settings file, openedx/tests/settings.py which made some debugging confusing because those tests had quite different django settings than other tests. This change deletes that file and runs the tests using the LMS test settings.
(3) The test suite also contains many different ways of initializing and testing a modulestore, with significant differences in their configuration, and also a lot of repetition. I find this makes understanding, debugging and writing tests more difficult. So this commit also reduces the number of different "test case using modulestore" base classes:
* Simplifies MixedWithOptionsTestCase and MixedSplitTestCase by making them simple subclasses of ModuleStoreTestCase.
* Removes PureModulestoreTestCase.
* 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 change will prevent Library Content from being marked as
complete on view and the corresponding version bump to
edx-completion contains code that will start looking at the
children of the library content for completeness.
