Base: forward port Headsup options (1/2)

-Global on/off
-Blacklist and Do not disturb
HeadsUp: add timeout option (1/2)
HeadsUp: Swipe options

-left swipe dismiss
-right swipe put into background
-swipe down opens notification drawer and moves the notification into it
HeadsUp: do not show if notification drawer is visible
HeadsUp: fix headsup for incoming calls
HeadsUp: enable by default

also remove unnecessary code
HeadsUp: fix settings not being applied after reboot

blacklist and dnd setting were not being applied at boot
clean up the SettingsObserver