Long-press power while display is off for torch

Long-press the power button while the display is off
to turn the torchlight on and off.

Credits:
 - Lion0738: The main hooks here:
   https://github.com/lion0738/android_frameworks_base/commit/9af2b7844a4d973c8b6c542d7937f56a24a7e5f1


 - Atlantis: The logic on where to hook into this for power button only
 - Alex Cruz: Helping and giving me some pointers along the way

Co-authored-by: Michael Bestas <mkbestas@lineageos.org>
Co-authored-by: Pranav Vashi <neobuddy89@gmail.com>
Co-authored-by: Sam Mortimer <sam@mortimer.me.uk>
Change-Id: I1aaf8417b865df79e8a1a8d0039b3b860a46be78