Add SCR to default karaf profile

Downstream projects are using OSGi DS (a.k.a. Service Component Runtime), which they depend on easily be depending on Karaf's "scr" feature. Unfortunately this results in rewiring of pax-logging, hence SFTs end up missing a chunk of their logs.

Promote OSGi DS to being equal to Blueprint and always load it. It is much better for OSGi than Blueprint anyway.