chore(ngUpgrade): Move into Angular2

This is moving ngUpgrade into the main repository per #4838.
The ngUpgrade is published from the main import consistent with
https://docs.google.com/document/d/1rbVTKTYLz6p2smQNYI8h4-QN-m2PS6F3iQIDmSzn0Ww/edit#heading=h.6cxvr9awtf5r
Closes #4931

modules/playground/src/upgrade/index.ts

@@ -1,5 +1,6 @@
 import {Component, Input, Output, EventEmitter} from 'angular2/angular2';
-import {UpgradeAdapter} from 'upgrade/upgrade';
+import {UpgradeAdapter} from 'angular2/angular2';
+import * as angular from '../../../angular2/src/upgrade/angular_js';
 
 var styles = [
   `