Use RRO for product-specific resources

Currently CompanionDeviceManager is compiled and linked with the
argument '--product {PRODUCT_CHARACTERISTICS}' to select
product-specific resources. But that causes the app to depend on the
product characteristics, making differences of system.img among
targets.

Setting generate_product_characteristics_rro will automatically
generate an RRO package which contains resources having
product="{PRODUCT_CHARACTERISTICS}"'. The RRO package will be
installed to /product partition. CompanionDeviceManager will be
compiled with '--product default', making system.img identical to all
targets.

Bug: 322932641
Test: TH
Change-Id: I0677e2e6c435ae9cfc4141c1ba7d569e3579ff69