Revert "refactor(platform-browser): move platform-browser/animations to animations/browser (#15043)"

This reverts commit 195b863ea4.

packages/animations/browser/src/render/web_animations/dom_animation.ts

@@ -1,19 +0,0 @@
-/**
- * @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
- */
-
-export interface DOMAnimation {
-  cancel(): void;
-  play(): void;
-  pause(): void;
-  finish(): void;
-  onfinish: Function;
-  position: number;
-  currentTime: number;
-  addEventListener(eventName: string, handler: (event: any) => any): any;
-  dispatchEvent(eventName: string): any;
-}