move nest stuff and cassandra driver wf module into its own repo

Right now, the bus repo is getting bloated with stuff that should not be in there. This grew out of my laziness and putting hawkular-nest under the hawkuar-bus repo. Now there is an equally unrelated component in the bus repo - cassandra-driver-wf-module.

We need to make the bus repo contain only those mvn modules related to the messaging subsystem.

So someone should create a hawkular-nest repo (or just put this under the hawkular repo somewhere? perhaps under modules? or under a new "nest" directory?) and move the hawkular-nest stuff (that you see in the bus repo) and the cassandra driver wf module to this new location.