remove notification led color options for devices with single color led

  -- due to several comments in forums regarding notification led color options I have added a resource check
       which is overrideable in device overlays and defaults to true
  -- this will remove all color and application configurations and leave only the option to enable / disable
       the notification led
  -- to remove the preferences in device overlays set:
       <bool name=config_multiColorNotificationLed>false</bool>

Change-Id: Iccf169a902a69cf8645df757d7d60cec9a0030f6