Settings: Add per app controls for LP keyguard notifications (2/2)

Nice done by google but the UX is a problem especially for ppl who are using a lot apps and just want
to see from important apps the notifications on the lockscreen.

This commit adds the ability to

- enable/disable per app the keyguard notification at all
- enable/disable per app ongoing notifications on the keyguard

We handle this over the app policy conf file like the other per app notification options

Change-Id: Ie4966f9048718c080571935796258625413f7344
Settings: Update AppNotificationSettings if user resumes

Right now if a user resumes this activty (eg from recents) and did change in the
mean time settings which effects the visibility of preferences in AppNotificationSettings
(eg were removed) it does not get updated.

Fix it with simply reloading the content on onResume and decide to show the entries
on the current user settings situation.

Change-Id: I0b16ebf35604fdca1611f026c9b609427f3060c8
Settings: less notifications sound (2/2)

Add back the 4.3 feature like it was.

User can setup how often notification sound
for an app comes trough so that
it does not annoy to much