[Tails-dev] Please review & merge referrer modifications

Hi!

I initially asked sajolida to review and merge this:
https://labs.riseup.net/code/issues/14561 But anybody could do it and I
have not received an answer from him over two weeks.

Ideally, this should be merged before October 15th. But if it's done
earlier, I will be able to update my other branches concerned with our
donation campaign and I'd be less stressed out about it.

So if anybody else has some time.. please take over the ticket.

Cheers!
u.