feat(gui): add webmanifest and icons

* Create site.webmanifest for SpootyFe

Add a web app manifest for SpootyFe with icons and theme colors.

* Add icons

src/frontend/public/favicon.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xlink="http://www.w3.org/1999/xlink" width="37" height="37" viewBox="0 0 37 37"><metadata><rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"><rdf:Description><dc:creator>RealFaviconGenerator</dc:creator><dc:source>https://realfavicongenerator.net</dc:source></rdf:Description></rdf:RDF></metadata><image width="37" height="37" xlink:href="data:image/png;base64,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"></image></svg>

src/frontend/public/site.webmanifest

@@ -0,0 +1,23 @@
+{
+  "name": "SpootyFe",
+  "short_name": "SpootyFe",
+  "description": "Self-hosted Spotify downloader",
+  "icons": [
+    {
+      "src": "/web-app-manifest-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "maskable"
+    },
+    {
+      "src": "/web-app-manifest-512x512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "maskable"
+    }
+  ],
+  "start_url": "./index.html",
+  "theme_color": "#1db954",
+  "background_color": "#14161a",
+  "display": "standalone"
+}