Publish/Subscribe image and logs

[shardros]

AS A consumer of logs
I WANT to be notified when a new event happens
SO THAT I don't have to poll
DONE IS

1. Logs/images are avaliable over a publish/subscribe interface
2. The old REST end points should still exist to support legacy code (the arena)
3. Sheep is updated to use this new socket based interface

NOTES:
This interface should also allow for a seperate
MQTT is one such publish subscribe interface which is already used in the arena