Display a QR code next to the activation link

[Menturan]

It would make the activation a bit smoother if you could just scan a QR code instead of having to type the address.

Could be realized by either showing an pregenerated image of the QR code or by generating one dynamically with this library.

[Kiina]

I tried to get an url that would prefill the form, but I guess trakt doesn't do that. As the URL is always the same, I don't see a good reason to generate one dynamically for now, but I included an svg in the latest release. Maybe alignment and stuff could be improved a bit, but I will do a 0.5 release soon with a few improvements