livedisplay: Add LiveDisplay settings

 * Add preference for LiveDisplay mode, and additional supporting
   options for auto mode.
 * CABC, SRE, CE are all under this umbrella now.
 * Manual RGB tweaking is now handled here and the requirement for
   CMHW has been removed as it will go thru RenderEngine.
 * Moved all related code into the livedisplay package.

Change-Id: I0b00f2bfd8f8227d64ad271bbe0f004f0b4bcf9d