This commit removes code that was used to copy Old Mongo courses into
new Split Mongo courses. This includes both the migrate_to_split
management command, as well as the backend code that would be invoked
to re-run Old Mongo courses as Split courses using Studio (the UI for
this was already removed in b429e55c).
This is a part of the Old Mongo removal effort tracked in:
https://github.com/openedx/public-engineering/issues/62
- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
- More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore
