Consolidate some device specific settings under device ~> "more.." header

The goal is to eventually create a "system parts" header when more options are added.
for now a helper class has been added to check/remove the "more..." header if it's
preference fragment is empty

note:
moved headset options to the same location (sound)
moved Active Notifications feature back to Notification drawer fragment and rename back
to Notifications

PS2: remove unnecessary booleans
PS3: move headset controls back to hardware keys and rename category Headset ~> Headset controls
PS4: split color control compat check into 2 booleans

Change-Id: I9a4b5f2a89656cbadb55d154d20cded17289836f