Docker image for RHT 4.12

Contributing code from https://github.com/gustavonalle/docker/tree/master/rhq, removing the documentation,
and the launch scripts.

**Building the image**

It's necessary to change ```build.sh``` with the right repository name of the image (it's still pointing to my personal repo) and run.it

**Running**
```git pull IMAGE```
followed by
```git run IMAGE``` (without /bin/bash since the ENTRYPOINT is supervisord)