WeblatePermission: Handle user renames correctly.
Create a userdb_cache that ships a username -> id link to check renames.
fixes: https://gitlab.torproject.org/tpo/tpa/tails/sysadmin/-/issues/18144
Create a userdb_cache that ships a username -> id link to check renames.
fixes: https://gitlab.torproject.org/tpo/tpa/tails/sysadmin/-/issues/18144