Task - RBAC AuthZ - M0 documentation

[rodmgwgu]

Create documentation for M0:

• Make sure ADR are in place (other ticket exists for this)
• Document Migration and Rollback strategy
• Known limitations are documented, and we have a short operational playbook for debugging and recovery during the transition.

Make sure the documentation is visible, either on the wiki or th repo.

[dwong2708]

Here is the deliverable: https://openedx.atlassian.net/wiki/spaces/OEPM/pages/5954502659/RBAC+AuthZ+Milestone+0+M0