[adapters] Use an adapter for serializing entities to a bare python structure which may be used for e.g. JSON export or other and allow to have different serializations for each entity types. Closes #6378035

sync_schema_props_perms('cwuri')

helper = repo.system_source.dbhelper
cu = session.cnxset.cu
helper.set_null_allowed(cu, 'moved_entities', 'extid', 'VARCHAR(256)', False)

commit()