Bug 8741: Fix broken Maven archetype

Bug 8741: Fix broken Maven archetype

Includes migration to Karaf 4 features, as per
https://wiki.opendaylight.org/view/Karaf_4_migration

The main goal here was just to get what I've found to be a completely
badly broken archetype; it even had some other other problems unrelated
to Karaf 4 migration; this looks like it had been haywire for quite a
while even before the Karaf 4 migration already?

This also contributes a basis for future automated self testing; see also
http://blog2.vorburger.ch/2016/05/how-to-make-maven-archetype-plugin.html,
but this is skipped in this change, because while it works great locally,
it fails for some strange reason related to SFT on (only) Jenkins.

I'm hoping that this just a very first step to ongoing active
maintenance of the archetype (by myself, but hopefully others too),
without ever breaking it anymore - thanks to the new self test. Here are
some possible future TBDs:

* remove archetype.test.skip and fix weird SFT problem (@vorburger)

* re-activate commented out IT which breaks during build self test

* odl-X* feature directory names with ${artifactId} instead of X
   (dunno how to get archetype to create folders named by variables)

* karaf.localFeature which breaks during build self test

* some clean-up e.g. remove useless site generation?

* real test of the produced Karaf distro? Using Pax Exam, but not *IT..

Change-Id: I013c305fb9b63cc965cbcc112cbe6017ae47de21
Signed-off-by: Michael Vorburger <vorburger@redhat.com>