move appbar from phonestatusbar to basestatusbar

also set it to unregister and register content observers conditionally as the setting is turned on/off

PS2: update for halo & fix appbar disappearance
PS4: Fixed all the tabs, spaces, and misalignments
PS5: Missed a couple.  100% finished now, I promise!

Change-Id: I7eb35a9d97c214e9e81de6872003ddaf9ef32e99