http://packages.synocommunity.com/
Pachage Center -> Comunity the "Mosquitto" pachage will be avalibile.
Once installed mine did not want to start until I restarted the Synology, you will have to SSH to the NAS to add the IP address and port.
/volume1/@appstore/mosquitto/var/mosquitto.conf
add the following lines using the vi editor under root
listener 9001
protocol websockets
Restart service from Package Center.