[server] extract "no pooler" CnxSet class to a _BaseCnxSet class
So we get rid of "if self._queue is None" in each method of _CnxSetPool
Also add helper get_cnxset(source, size) to instantiate the correct pooler class.
sync_schema_props_perms('cw_source', syncprops=False)
if schema['BigInt'].eid is None:
add_entity_type('BigInt')