Revert "[2/3] Telephony: allow disabling non intrusive incall ui"

This reverts commit 868a6c403fe7b775d9d91546d17fc1a19d564714.
Telephony: Incoming Call in Background (2/3)

Patch ported from 4.2 which was done by our lovely HCP. A
very popular one so we bring it back and adapt it to 4.4

Allows user to set that Incoming Call UI will remain in background
if screen is on. Instead, a notification is added to StatusBar, which
can be used to bring up the Incoming Call UI. Ringtone and vibration
still occur as per system settings.

This has the same effect as apps marked as "immersive". It prevents
the incoming call from backgrounding the current activity.

PS: reorder settings a bit

Change-Id: I159bd817ebcc39a0733f9433feb29b310adbc2aa
[2/3] Flip to Mute/Reject Call

Call Settings - add menu entry

PS:
- fix not sticking entry

PS:
- correct idention from the whole xml file

PS:
- add a personal settings category to have the settings better sorted and splitted

Change-Id: Ic011c5b9e10439fc900b1302f7e07dde494b2e5b