Add Android 5 theme colour

public/views/index.html

@@ -4,6 +4,7 @@
     <meta charset="utf-8">
     <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
     <meta name="viewport" content="width=device-width">
+    <meta name="theme-color" content="#000">
 
     <title>Grafana</title>