Make the enabled property configurable

This allows using select statements with it.

Ignore-AOSP-First: This needs to be in a topic with changes in interal-only repositories, I'll cherrypick to aosp after.
Bug: 323382414
Test: m nothing --no-skip-soong-tests
Change-Id: I6f3efaaa3d82505e38a91ee4ba0e18e404360191

rust/rust.go

@@ -1697,7 +1697,7 @@ func (mod *Module) DepsMutator(actx android.BottomUpMutatorContext) {
 }
 
 func BeginMutator(ctx android.BottomUpMutatorContext) {
-	if mod, ok := ctx.Module().(*Module); ok && mod.Enabled() {
+	if mod, ok := ctx.Module().(*Module); ok && mod.Enabled(ctx) {
 		mod.beginMutator(ctx)
 	}
 }