add basic home, admin pages

- index no longer requires login, it's just a big fat login button
- home has stop, start, admin buttons
- admin doesn't do anything yet
- add jhapi javascript client for REST API

share/jupyter/static/js/home.js

@@ -0,0 +1,19 @@
+// Copyright (c) Jupyter Development Team.
+// Distributed under the terms of the Modified BSD License.
+
+require(["jquery", "jhapi"], function ($, JHAPI) {
+    "use strict";
+    
+    var base_url = window.jhdata.base_url;
+    var user = window.jhdata.user;
+    var api = new JHAPI(base_url);
+    
+    $("#stop").click(function () {
+        api.stop_server(user, {
+            success: function () {
+                $("#stop").hide();
+            }
+        });
+    });
+    
+});