Provide Karaf 4 specific features and commands

There are a few shortcomings when using the existing features in Karaf 4.x.
Creating specific features and commands will allow:

• to not depend on blueprint
• to validate the feature definitions correctly
• fix existing features

In addition some features have a strong dependency on jetty, while Karaf 4.1 will provide a choice for the http / war provider (jetty, tomcat, undertow), so it would make sense to refactor some features to better leverage those possibilities.