fb: add back notification shortcuts feature + common slim classes

    beside our unique slim feature this patch adds

    - all system shortcut icons we need for this and other stuff in future
    - basice slim helper and constants classes we need later as well
    - device utils helper
    - preparation for navbar navring and other shortcut features
    - and of course our notification shortcuts feature

Change-Id: Ic2f3366c85d2cb9be324b762e3510c7630caad24
Signed-off-by: Scott <scott@ubuntu>