Add in OAuth authentication to Isolate Polymer UI

appengine/isolate/ui/res/imp/index/isolate-index.html

 <!--
   Copyright 2017 The LUCI Authors. All rights reserved.
   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
 
   This in an HTML Import-able file that contains the definition
   of the following elements:
 
     <isolate-index>
 
@@ skipping 10 matching lines @@
     client_id: String, Oauth 2.0 client id.  It will be set by server-side
         template evaluation.
 
   Methods:
     None.
 
   Events:
     None.
 -->
 
+<link rel="import" href="/res/imp/common/isolate-app.html">
+
 <dom-module id="isolate-index">
   <template>
-    <style>
-      h1 {
-        color:purple;
-      }
+    <style include="isolate-app-style">
     </style>
 
-    <h1>Hello World</h1>
-
-    <div>{{client_id}}</div>
+    <isolate-app
+      client_id="[[client_id]]"
+      auth_headers="{{_auth_headers}}"
+      permissions="{{_permissions}}"
+      server_details="{{_server_details}}"
+      name="Isolate Server">
+      This is an isolate app placeholder.
+    </isolate-app>
 
   </template>
   <script>
     Polymer({
       is: 'isolate-index',
 
       properties: {
         client_id: {
           type: String,
         }
       },
 
     });
   </script>
 </dom-module>