Protect cached upstream entities from local edits

Block edits to configured low-numbered P/Q entities in the local Wikibase
and direct users to edit the upstream source instead.

This keeps locally cached upstream entities stable and supports resilience
when the upstream Wikibase is temporarily unavailable, in line with the
caching rationale discussed in:
https://doi.org/10.3389/frma.2022.861944

Change-Id: Id135402e060bbaa3b2df8cd4551623e11ba06e25
5 files changed