Introduce MobileDataAlwaysOnPreferenceController

 - Create new MobileDataAlwaysOnPreferenceController
 - Create controller inside the DashboardFragment
 - Port logic from DeveloperSettings into the controller

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: If4b1a0d14c4b24cb1562a37627436bfb011e9310
3 files changed