Add TWRP app install via TWRP recovery

Note: I will have to add a build flag for excluding the app later for
watches and maybe Android TV. I will also have to add support in the
tablet and watch layouts later. I will merge this for the initial roll out
to select devices and finish up later.

Change-Id: Ia4ce5522fae542afa1539b10c0691315392a19ab