display per-instance statistics

server/templates/instance_errors.html.j2

@@ -7,11 +7,11 @@
     <meta name="robots" content="noindex,nofollow" />
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <meta name="author" content="" />
-    <title>Admin Interface</title>
+    <title>Error | {{HOST_DOMAIN}}</title>
   </head>
   <body>
     <div class="container">
-    <h1>Admin Interface</h1>
+    <h1>Last errors for {{HOST_DOMAIN}}</h1>
     <p><a href="/admin">Overview</a> <a href="/admin/logout">Logout</a> <a href="/admin/login">Add more instances</a></p>
     <div><canvas data-host="{{HOST_ID}}" id="graph" width="600" height="200"></canvas><noscript>History feature works only with javascript enabled.</noscript></div>
     <div class="container mt-5">