[2/2] Settings: On-The-Go mode

On-The-Go turns on the camera of your phone and streams it to an overlay,
which is drawn over everything.
this makes you feel like your display is transparent, as you see the content
behind it.

its really useful when you are using your phone while walking, thats why
we called it "On-The-Go"

have fun!

Change-Id: I31c03d9e02c238e237681354b3991a0427c0c47b
This option is for Slim Recents
[2/2] Settings: On-The-Go: Add quicktile

Also thanks to @Alex-Cruz for all these nice talks, which improved the
quality of the On-The-Go mode :)

PS 2:
On-The-Go drawables, made by Alex-Cruz, thanks!

Change-Id: I30d8232746ac0a0bd5ccfbfba435e0ac1658becb
[2/2] Settings: On-The-Go: Hide on devices without camera

Hide camera switching for devices without front camera as well
if we dont have a front camera, open the first camera we have.
also hide the options from the dialog.

Change-Id: Ic74579708dc4ff030cca97f1f5972dce105431d8