[CLOSED] FC-0004 - Old Mongo Deprecation

The project will focus on the deprecation of the “DraftModuleStore” (also referred to as "Old Mongo”) and
is defined in this issue on the public roadmap (https://github.com/openedx/platform-roadmap/issues/3. As described in the issue link, “Old Mongo'' is no longer widely used and thus no longer providing added value. Removing these items will allow NP to reduce cost and maintenance burdens, simplify the system, and thereby scale platform adoption.

The priority work is listed in depth in issue #62 and includes the following:

● Remove Studio access for Old Mongo courses. #75
https://github.com/openedx/public-engineering/issues/75)
● Remove code related to Old -> Split Migration #76
https://github.com/openedx/public-engineering/issues/76
● Remove the ability to read and write static assets to Old Mongo #77
https://github.com/openedx/public-engineering/issues/77
● Opportunistically Remove Old Mongo Tests #78

● Remove inheritance-related code from Old Mongo #79

● Remove support for children in Old Mongo #80