Add GWT Archetype to JBoss central

As per Burr's request, we need to add a GWT archetype to the "New Project" section of JBoss Central under the name "GWT Web Project".

First thing is to get the Errai team to provide the archetype GAV and repository informations, then reference it in http://anonsvn.jboss.org/repos/jbosstools/trunk/download.jboss.org/jbosstools/examples/project-examples-shared-3.3.xml

The icon will be : from the EPL'ed GEP project.