LineageSettingsProvider: Support migration from cmsettings

*) Migrate database from cmsettings.db to lineagesettings.db

*) Remove old CMSettingsProvider.xml shared_prefs.

*) Remove the code to disable the PreBootReceiver component.
   PackageManager is not yet ready for component lookups when
   LineageSettings is called during fw/b service startups.
   However, the preboot intent is only sent when the build
   fingerprint changes so disabling it doesn't really buy us
   anything.  We also track and check migration state in
   sharedPrefs anyway.

Change-Id: I636f8315ce8a36f6d223d6a5accfe11c40ef9570