Karaf cleanup and improvements

[maggu2810]

I think we should merge it.
The TODOs are okay for a development branch.
The merges of the master branch should be integrated into this one.

• do a lot of cleanup of the features
• drop a lot of unnecessary dependencies
• work with Eclipse Equinox and Apache Felix OSGi framework
• using up to date Event Admin and SCR
• @kaikreuzer shk-feature-base XML is added to temporary maven repo (special snapshot version for OH2 only)
• drop internal workarounds for KAR packaging etc.
• implement a working feature verification

Todo:

• Jetty is currently using the Pax Web default configuration, so it runs on port 8181 and does not redirect to start/index. But it is working (use: http://127.0.0.1:8181/start/index)
• The rest documentation (with swagger) should be working as soon as the other upstream master bugfixes are merged.
• future verification is working, but disabled. It will fail ATM because of missing already done changes in upstream master (should be working as soon as the other upstream master bugfixes are merged).