Revert "Settings: Remove unnecessary padding from HeadsUpSettings."

This reverts commit b6b1ef3c8455d6365657edc32e38178de504902d.
Revert HeadsUp commits

https://github.com/AOSB/android_packages_apps_Settings/commit/ec72ee11f06b359e6514b6e3467af32fc32704f3
https://github.com/AOSB/android_packages_apps_Settings/commit/0001abce8d1a3ce5148ff8159b29b250c98e5553
https://github.com/AOSB/android_packages_apps_Settings/commit/b6b1ef3c8455d6365657edc32e38178de504902d
https://github.com/AOSB/android_packages_apps_Settings/commit/e4bbba1aef933ce22dfb768eadfc521244a2ff35
Settings: Heads up meets SlimKat....SlimKat meets Google IO [4/4]

For detailed explanation see here: https://gerrit.slimroms.net/#/c/9937/

This patch adds the 4 possible user configurable settings.
1. Enable always expanded heads up notifications.
2. Set heads up snooze time
3. Set timout timer
4. Show updates of pending notifications
5. Add in app info screen a checkbox to enable heads up for the app.
   As another possibility aside the longpress on the notification on
   notification drawer.
Settings: Show heads up at the bottom of the screen (2/2)
Due of user requests and indeed especially on hw key devices for a better
workflow we add an option to show heads up notifications on the bottom instead
of the top.

Animation we leave as is due that if it slide from the bottom into the screen it happens
to often that the user accidentaly interacts with it. If it comes from the top of the
container we add, the user has enough time to realize it. Sometimes a ms can make a big difference.
fix build @c1c8783f02