[Hawkular-dev] Version endpoint for components

[Heiko W.Rupp]

Hey,

I think it would be good for all components that have a REST interface
to have a /version endpoint that responds on GET and which returns
- the tag (e.g. 0.8.1.Final or  0.3.44-SNAPSHOT or 1.2.3-src-dep-0xcafebabe))
- the git hash they are built from (less needed for .Final)

So that clients can easily verify what version they have as peer.