Frameworks: reduce navbar observer footprint (1/2)

time for code cleanup projects. Switch to same
logic we already use in QS/NT shortcuts. Use
only one string for the whole navbar config
This reduces massive the observer footprint.

NavRing and SlimPie will follow with same logic

cheers

Change-Id: Ie484bf72ae6e9cefa5cd979bbb279fa8549b8fdf