feat(common): add @angular/common/upgrade package for $location-related APIs (#30055)

AngularJS's `$location` service doesn't have a direct counterpart in Angular. This is largely because the `Location` service in Angular was pulled out of the `Router`, but was not purpose-built to stand on its own.

This commit adds a new `@angular/common/upgrade` package with the beginnings of a new `LocationUpgradeService`. This service will more closely match the API of AngularJS and provide a way to replace the `$location` service from AngularJS.

PR Close #30055

packages/common/upgrade/public_api.ts

@@ -0,0 +1,16 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * @module
+ * @description
+ * Entry point for all public APIs of this package.
+ */
+export * from './src/index';
+
+// This file only reexports content of the `src` folder. Keep it that way.