Recent migration from the scrubber which did not comply fully with the documentation 
in regards to migration (through swh db upgrade cli) started some work to fix it .
The migration for the scrubber was fixed but broke some other modules as side-effects.
After further discussion with @douardda regarding the multiple proposed and somewhat
wrong implementations, we've come to an understanding and a proper plan to fix
- Keep the current core code  (swh.core v2.10 with code and doc ok and aligned)
- D7953: Fix swh.storage's datastore to add the attribute current_version
- D7954: Fix swh.indexer's storage datastore to add the attribute current version
- Drop unnecessary reverting diff  (again core code is actually ok providing ^)
- Drop diff  which is irrelevant as it does not fix (I misunderstood the code)
- D7958: Clean up unneeded code in scheduler
- T4305#86415: Checks