Mms: Add native heads up support

Add heads up support (optional but enabled by default).

Shows important messages of this app as heads up.

Means:
- All MMS
- SMS if quickpopup is disabled

Other messages like storage or blacklist notifications are not important and will not show as heads up

PS:
- show always as expanded.....so user can directly interact with it

Adapted for LP

all other features are already back in Mms package

we still need to Materialize it

Change-Id: Id83633610c18ab4e380bfb910ea50e8bf7b61be6
Mms: change to switches and small cleanups

Change-Id: Ic3473eaae74a040b4f61961e8607ab8e710f6262