Implement new method for handling SMS/MMS on the platform

Multi project change:
The changes in this project update the settings app to support the new
default SMS app setting. I have also updated the order of the wireless
settings in the UX as per request from rachelg.

Bug: 10449618
Change-Id: Iba1ac6ea3f29c2a72af83b122ec5ea3a16a28e58