Offline troubleshoot when server disconnects

Summary:
If there server disconnects, we used to show a red box message on the lower left section of the screen. It didn't say much other than the server had disconnected.
If you are aware of what the server is, then you may try to manually restart it.

Instead of doing that, a much better experience is to show the no connection troubleshoot with the button to start the server or with instructions on how to achieve this.

Reviewed By: antonk52

Differential Revision: D48467308

fbshipit-source-id: 0ffded95789c7548d9f1e1a9127409e02e72ab8c

desktop/static/offline.html

@@ -42,17 +42,16 @@
       height: 250px;
       box-sizing: border-box;
       margin: auto;
-
     }
 
     .console header {
       border-top-left-radius: 15px;
       border-top-right-radius: 15px;
-      background-color: #4267B2;
+      background-color: #9254de;
       height: 45px;
       line-height: 45px;
       text-align: center;
-      color: #DDD;
+      color: white;
     }
 
     .console .consolebody {
@@ -67,6 +66,25 @@
       text-align: left;
     }
 
+    input[type="submit"] {
+      background-color: #9254de;
+      color: white;
+      font-family: system-ui;
+      font-size: 15px;
+      padding: 10px 20px;
+      border: none;
+      border-radius: 5px;
+      cursor: pointer;
+    }
+
+    input[type="submit"]:hover {
+      background-color: #722ed1;
+    }
+
+    input[type="submit"]:active {
+      background-color: #722ed1;
+    }
+
   </style>
 </head>