Address the 'ART' Issue

Rather than outright remove this completely, address primary concerns:

* Add a more verbose warning message on alert dialog
* Explicitly state experimental form
* Explicitly state not supported (no bug reports)
* Explicitly state issues (crashes, bootloop, etc)

Additionally, move option to 'Apps' header (bottom), as this is it's
primary impact.

Change-Id: Icf103b5576c8e93f8a30ccd348476bf207401355