chore: update to modern favicon

Author: IgnaceMaes

app/index.html

@@ -12,7 +12,11 @@
 
     <link integrity="" rel="stylesheet" href="{{rootURL}}assets/vendor.css">
     <link integrity="" rel="stylesheet" href="{{rootURL}}assets/ember-guides.css">
-    <link rel="shortcut icon" href="/images/favicon.png" />
+
+    <link rel="apple-touch-icon" href="/favicons/apple-touch-icon.png">
+    <link rel="icon" href="/favicons/favicon.ico" sizes="any">
+    <link rel="icon" href="/favicons/icon.svg" type="image/svg+xml">
+    <link rel="manifest" href="/favicons/manifest.webmanifest">
 
     {{content-for "head-footer"}}
   </head>

public/images/favicon.png

@@ -0,0 +1,7 @@
+{
+  "name": "Ember.js",
+  "icons": [
+    { "src": "/favicons/icon-192.png", "type": "image/png", "sizes": "192x192" },
+    { "src": "/favicons/icon-512.png", "type": "image/png", "sizes": "512x512" }
+  ]
+}