Add basic PWA support (#38) (#210)

* Add basic PWA support

See: https://github.com/gpxstudio/gpx.studio/issues/38

This will add a basic manifest.json file to the response that creates an
installable PWA.

It still needs to be internationalized.

* Refactor PWA integration and update dependencies

- Removed @vite-pwa/sveltekit dependency and related configurations from package.json and vite.config.ts.
- Added prebuild script to generate PWA manifest before build.
- Moved the manifest link to hooks.server.js and included Apple touch icon.
-Added images for various platforms. Images were generated with https://www.pwabuilder.com/imageGenerator

* use svg icon, fix urls, and remove generated manifest files

---------

Co-authored-by: jonherman <jonherman@gmail.com>
Co-authored-by: vcoppe <vianney.coppe@gmail.com>

website/static/en.manifest.webmanifest

@@ -0,0 +1,18 @@
+{
+  "name": "gpx.studio",
+  "short_name": "gpx.studio",
+  "description": "View, edit, and create GPX files online with advanced route planning capabilities and file processing tools, beautiful maps and detailed data visualizations.",
+  "start_url": "/app",
+  "display": "standalone",
+  "lang": "en",
+  "scope": "/app",
+  "id": "https://gpx.studio/app",
+  "icons": [
+    {
+      "src": "icon.svg",
+      "sizes": "any",
+      "type": "image/svg+xml",
+      "purpose": "any maskable"
+    }
+  ]
+}