Introduce module type aconfig_declarations_group

In order to easily manage aconfig_declarations modules and their
corresponding codegen modules, this change introduces a new module type
`aconfig_declarations_group`. The module enables listing codegen modules
by language, and correctly depend on the desired output files using
appropriate tags.

e.g. for an aconfig_declarations_group module "some_group", the rdeps of
the module can:
- gather all intermediates cache files of the aconfig_declarations with
  ":some_group" tag.
- gather generated srcjar files of the listed java_aconfig_library
  modules with ":some_group{.srcjars}" tag.

Output tag support for cc modules and rust modules will be added in
future changes.

Test: m nothing --no-skip-soong-tests
Bug: 320492079
Change-Id: I93d737577f8d00198ed91048dd6e81ef238193cb

aconfig/codegen/java_aconfig_library.go

@@ -17,6 +17,7 @@ package codegen
 import (
 	"fmt"
 
+	"android/soong/aconfig"
 	"android/soong/android"
 	"android/soong/java"
 
@@ -118,6 +119,12 @@ func (callbacks *JavaAconfigDeclarationsLibraryCallbacks) GenerateSourceJarBuild
 		module.AddJarJarRenameRule(declarations.Package+".FakeFeatureFlagsImpl", "")
 	}
 
+	android.SetProvider(ctx, aconfig.CodegenInfoProvider, aconfig.CodegenInfo{
+		AconfigDeclarations:          []string{declarationsModules[0].Name()},
+		IntermediateCacheOutputPaths: android.Paths{declarations.IntermediateCacheOutputPath},
+		Srcjars:                      android.Paths{srcJarPath},
+	})
+
 	return srcJarPath
 }