Use soong built autogenerated RROs

At ToT, soong emits metadata to make (LOCAL_SOONG_PRODUCT_RRO_DIRS and
LOCAL_SOONG_DEVICE_RRO_DIRS), and make uses this metadata to build and
install apks that are intalled in /vendor or /product. This CL ports
this logic to soong.

This CL autogenerates these modules in a load hook for android_app and
override_android_app, and adds them to the `LOCAL_REQUIRED_MODULES` of
the base app. The autogenerated modules will inherit the enabled
property of the apps. This required me to add `Target.Android.Enabled`
to commonProperties in ModuleBase.

Since autogeneration happens in soong now,
`LOCAL_SOONG_(DEVICE|PRODUCT)_RRO_DIRS` no longer needs to be exported.

Followup work
- Installing the overlay variants for soong built filesystems.

Test: lunch aosp_cf_x86_64_phone-trunk_staging-userdebug
Test: no diff in system, vendor, product file_list.txt
Test: m out/target/product/vsoc_x86_64/vendor/overlay/SystemUI__aosp_cf_x86_64_phone__auto_generated_rro_vendor.apk

the apk is not bit-identical, but this is likely due to different
aapt link flags between make and soong (e.g. `--enable-compact-entries`
is added as default in soong but not in make
Test: aapt2 diff
SystemUI__aosp_cf_x86_64_phone__auto_generated_rro_vendor.apk.before
SystemUI__aosp_cf_x86_64_phone__auto_generated_rro_vendor.apk.after
reports no diffs

Change-Id: I9b212a4ed443250a63dbe27cb955c6f133cff9af
diff --git a/android/module.go b/android/module.go
index 67dab4f..6d2c39b 100644
--- a/android/module.go
+++ b/android/module.go
@@ -338,6 +338,7 @@
 		}
 		Android struct {
 			Compile_multilib *string
+			Enabled          *bool
 		}
 	}