Add icons, apply as favicons for dashboard

dashboard/index.html

@@ -4,6 +4,9 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Serena Dashboard</title>
+    <link rel="icon" type="image/png" sizes="16x16" href="serena-icon-16.png">
+    <link rel="icon" type="image/png" sizes="32x32" href="serena-icon-32.png">
+    <link rel="icon" type="image/png" sizes="48x48" href="serena-icon-48.png">
     <script src="jquery.min.js"></script>
     <script src="dashboard.js"></script>
     <style>