Better UI for showing messages after loading finished

[rugk]

The placeholder (the grey QR code) actually should only be shown when the QR code itself is not available. However, currently it is also often shown when the QR code is already there and something else happens…

What should happen: Probably we can just add some opacity (or blurring or so) or so to the existing QR code, so it is still obvious that there is something that requires attention, but the QR code should still be there.

E.g.:

• when you try to "Save as…" the QR code as an SVG and have not yet granted the "download" permission, a info message (and the placeholder replacing your nice precious image/QR code) is shown.

[Yzmoo]

Hey! Can I work on it?