Make new UI be the default UI

appengine/swarming/ui/res/imp/common/swarming-app.html

 <!--
   Copyright 2016 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:
 
     <swarming-app>
 
@@ skipping 85 matching lines @@
       paper-spinner-lite {
         --paper-spinner-color: var(--google-yellow-500);
       }
     </style>
     <app-header-layout>
       <app-header fixed>
         <app-toolbar>
           <div class="title left">[[name]]</div>
           <paper-spinner-lite class="left" active="[[_or(busy,_busy1,_busy2)]]"></paper-spinner-lite>
 
-          <a class="left" href="/newui/">Home</a>
-          <a class="left" href="/newui/botlist">Bot List</a>
-          <a class="left" href="/newui/tasklist">Task List</a>
+          <a class="left" href="/">Home</a>
+          <a class="left" href="/botlist">Bot List</a>
+          <a class="left" href="/tasklist">Task List</a>
           <div class="flex"></div>
+          <a class="small right" href="/oldui">Old UI</a>
           <div class="small right">
             Server:
             <a href$="[[_versionLink(server_details)]]">
               [[server_details.server_version]]
             </a>
           </div>
           <auth-signin
               class="right"
               client_id="[[client_id]]"
               auth_headers="{{auth_headers}}"
@@ skipping 180 matching lines @@
         border: none;
         line-height: 20px;
         vertical-align: middle;
       }
 
       select {
         overflow-y: auto;
       }
   </style>
 </dom-module>