[cwctl] rewrite wsgi method choices This will help devs to add new choices by adding their callback to WSGI_CHOICES. Note: ``options`` becomes a property because ``wsgichoices()`` should be evaluated at the last-minute.

drop_relation_definition('CWSourceSchemaConfig', 'cw_schema', 'CWAttribute')
sync_schema_props_perms('cw_schema')