Create the obsolete version of the belowing fragments, so we could
flip between old page and new page.
BluetoothSettingsObsolete and DeviceListPreferenceObsoleteFragment
contains all the old logic but:
1. Logic about BluetoothPairingPreferenceController(ag/2239482),
since this preference shouldn't be checked in without the flag :(
This cl also adds logic in MasterSwitchPreferenceController to flip
these two pages.
Following cl will refactor these fragment to make it compatible
to new framework.
Bug: 35877041
Test: RunSettingsRoboTests
Change-Id: I1cc1bc2d49d8a3e11c3127e56f6409fbc84028d8
