Add Code Metadata rule to soong/testing.

This Cl adds a new rule to Soong to generate code ownership metadata. Also, this CL adds a provider in the Java SDK library to provide generated source files to the Code_metadata rule. Will add providers to other libraries in the future changes.

Bug: 296873595
Change-Id: Ic2e43aa9b161231fea4416d1f0d36b778361d7c5

testing/init.go

@@ -28,6 +28,8 @@ func init() {
 }
 
 func RegisterBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("code_metadata", CodeMetadataFactory)
 	ctx.RegisterModuleType("test_spec", TestSpecFactory)
+	ctx.RegisterParallelSingletonType("all_code_metadata", AllCodeMetadataFactory)
 	ctx.RegisterParallelSingletonType("all_test_specs", AllTestSpecsFactory)
 }