Maven packaging for feature, kar, karaf-assembly; mojos based on geronimo server assemblies

This overlaps with quite a few other jiras.
This work adds mojos for:

feature xml generation with one feature per maven project, following the appropriately scoped maven dependencies. This is very different from the existing feature.xml generation which has apparently not proved useful. We stop following transitive dependencies when we reach another maven dependency that's a feature.

kar assembly including the feature.xml file as above, maven dependencies, and resources.

Server assembly which installs the kars listed in the pom; kar installation uses the existing kar deployer
server archiving which packs up the assembled server into tar.gz and zip files

and also maven packagings for these.

In addition there's a framework kar that includes the basic file structure for a karaf server and the stuff that isn't in the local-repo and a sample server assembly that just has the framework in it.