[schema deserial] fix loading of schema when mapping an entity type to an existing one To ensure rdef of the old entity type don't overwrite those already existing on the mapped entity type. Also rename some variables/arguments on the way to make things clearer.

[migration] more rename_entity_type fix * ensure repository caches and system tables are properly cleanup * delete relations from/to entities deleted through sql So we don't ends up with a corrupted db...

cleanups

[integrity] fix case where we can get two entities related while the cardinality is single on the object of an inlined relation