Hover add customizations [2/2]

floating mode
duration
require fullscreen
all force remove non-removable items
hide low priority items
hide non removable items
centralize excluded app list (dynamically updates with app's preference screen)

PS2: update dependencies based on enabled state
PS3: fix NPE for null excluded apps string
PS4: clean up a couple strings

Change-Id: I2a60a6795c2b01b8194c54030e0a947ec1805ec3