Summary:
With the current setup, the final aar contains `com.facebook.proguard.annotation.DoNotStrip`. This is not needed (it is only used for proguard), and thus should not get published.
We move proguard annotations into its own project for this, and place it into `java/proguard-annotations`. Here we adopt the gradle convention of `src/main` to make for a nice, clean (one line!) gradle script. As a different subproject, we can include this to `:yoga` as a `provided` dependency now, which doesn't include it in the output artifact.
Reviewed By: emilsjolander
Differential Revision: D4666572
fbshipit-source-id: a0cb26cb6c264065a0bd355b7d72ba02e3759560
