Archetypeimporvements

I add some improvements to the arcehtype.
* maven release plugin for release management of archetype & project template
* add jetty-distribution in silo-template
* update some dependency versions
* group id will be now ```com.rebuy.service``` and not ```com.rebuy.service.<domain>``` anymore

@bjoernhaeuser @poljaric @dfreudenberger @omares 
Give me some feedback, please!