Refactor IMEAndLanguageSettings to use PreferenceController

Bug: 32642706
Bug: 32637613
Bug: 32643833
Test: RunSettingsRoboTests

This change is necessary to test preference controlling logic, as well
as making preferences reusable in other Preference pages in the new
information architecture.

Change-Id: I9e2fd2f6800579f005a5c303ed03ae06477006a6