Settings: Remove Performance Settings

* The CPU settings code is archaic and most devices don't need/require it anymore,
  especially due to per-app profiles.
* Nuke the Performance dashboard preference, moving the Per-App Profiles to Battery Settings, and High End Gfx options
  to Development Settings.

Change-Id: I37a498777b34691c72f458cb594170e6bddecc81
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>