Make QR code exportable as image

[Resaki1]

Currently, the QR code to share a session is rendered as an SVG. Right-clicking it does not give the option to save the QR code as an image (at least in Chromium). Of course you could make a screenshot, but rendering it as an image would make it easier imo

[brandstetterm]

I really like your suggestion and I think we should do it!
At first I was wondering how this would be useful and why you would want to download the QR code. But after thinking about it for a while, I came to the conclusion that you might want to embed the QR code into something like a picture, poster, etc.