Introduce afdo

A new configuration rule for sampling PGO. This differs from the
original pgo.go rule in the following ways:
 * Automatic propagation to static dependencies
 * Simpler configuration (just put `afdo: true` to optimsation targets)

http://go/android-afdo

Test: build
Bug: 79161490
Change-Id: Ie194824cd523bca19e10ced41d2078fc598f13b3