Allow changing screen-off animation (1/2)

* Allow enabling/disabling screen-off animation
* Allow selection between fade & crt effects if the device allows it

Change-Id: If6bb9afd7a753e1df013e88f7f39cea94e8fe565
Allow configuration of the default screen-off animation style

Change-Id: Ib59f8fce45c11193104682b975ff6467df8cfc15
derp @e6229eff