Add use_websockets == exclusively for cloudi_service_http_cowboy to limit usage of a port to websockets-only. Add websocket_connect_async, websocket_connect_sync, websocket_disconnect_async, and websocket_disconnect_sync to cloudi_service_http_cowboy to handle (blocking) connection validation (i.e., synchronous connect service requests with websocket_connect_sync, websocket_connect remains the same as websocket_disconnect_async).