fw: Move Global settings to CMSettings

This moves all Settings.Global.* settings, that were added to
CyanogenMod and not used in boot classpath, to CMSettings.

 * WAKE_WHEN_PLUGGED_OR_UNPLUGGED
 * BLUETOOTH_A2DP_SRC_PRIORITY_PREFIX
 * POWER_NOTIFICATIONS_ENABLED
 * POWER_NOTIFICATIONS_VIBRATE
 * POWER_NOTIFICATIONS_RINGTONE
 * ZEN_DISABLE_DUCKING_DURING_MEDIA_PLAYBACK
 * WIFI_AUTO_PRIORITIES_CONFIGURATION

Change-Id: I5a23971b278d150c633d2b4ade49a143c4423c26