Have a QR in UI so it can be shared easily

- experiment with creating a QR on the source address of the app (so you can reuse it in all your apps) and on how you can display that QR
- it should allow for the user to show the QR and for another to use their phone camera and navigate to the PWA's source URL 
- important to make it reusable with as few customizations as possible (generate an image, or better yet an SVG ?)