Add an option to use Starlark-based configuration by default.

In order to use Starlark-based product and board configuration for
a product, add its name to the STARLARK_OPT_IN_PRODUCTS list in
the AndroidProducts.mk file where this product is defined.

Fixes: 220379303
Test: Temporarily added STARLARK_OPT_IN_PRODUCTS to build/make/target/product/AndroidProducts.mk
Change-Id: Iacd23cec00a7a1958701873bce0fc9d5f79b1f17