orpaned docker containers and unused image cleanup

[tsukhu]

If we continuously keep building and running containers there are a lot of orphaned containers and old images that get accumulated on the docker machine. A new script is created that the user can run to clean up his environment and save on disk space as well.

Future enhancement: Ideally this can be integrated with the maven build process so that during a 'mvn clean' call this script is called to take care of this automatically.

[kucharzyk]

Script is good but for maven integration we can't assume that developers using linux or max. It won't work for windows users