Clean up and improve RGB LED code.

- Improve battery usage by using AlarmManager instead of keeping a
  wakelock when cycling through colors
- Rename stupidly named LED configuration settings key
- Use intent based communication with CMParts instead of writing random
  files
- Streamline code
- Optimize settings DB accesses
- Share random color list with CMParts
- Implement improvements done in CMParts change
  I6fb4d2ef8ddce5aaed83ef6b21f87868620f5c16

Change-Id: Iaf2a930ecf6393980e5648c89aa8c04ec7c0d337