feat(pwa): installable manifest and icons

src/app.html

@@ -5,6 +5,9 @@
     <meta content="width=device-width, initial-scale=1" name="viewport">
     <meta content="scale" name="text-scale">
     <link href="%sveltekit.assets%/favicon.svg" rel="icon" type="image/svg+xml">
+    <link href="%sveltekit.assets%/manifest.webmanifest" rel="manifest">
+    <link href="%sveltekit.assets%/icon-192.png" rel="apple-touch-icon">
+    <meta content="#3c8dbc" name="theme-color">
     %sveltekit.head%
   </head>
   <body data-sveltekit-preload-data="hover">