ADR for removing MongoDB from edx-platform

Overdue ADR PR:

I’ll keep it open for a couple of weeks to give folks time to comment.

Thank you.


This has been merged.

PRs related to this effort:

I’ll add more PRs to this thread as they come, for folks who are interested in following this. Thank you.

The second of three PRs needed to switch the handling of active versions to MySQL has merged:

The previous PR had to be reverted again, and now Take 3 of the data migration for course index data has been merged: