rework immersive mode => immersive desktop

add ability to show only the navbar in immersive style
add expanded desktop to disable swipe to show UI gestures
add low profile mode to dim the UI within an app
temp: add a custom charsequence array to set immersive style entries
for navigation barless devices.

to do: after navbar is fixed for devices with hardware keys add provisions
to use custom charsequence only when navbar is disabled.

PS2: modify confusing dependencies
PS3: fix immersive reboot dialog update when toggled from systemuisettings fragment

Change-Id: Ia01caa259a0b4b04a1fd0d3312ce9b9c2d76f129