Tails' torrents are using defunct tracker.coppersurfer.tk

A user reported this to us, calling it "long defunct", so we shouldn't just find a replacement, but also put in a process to make sure we use active trackers. Looking at #9277 (closed) we had various criteria around it being open and allegedly not logging much, so we should codify that and include checking if those are still true as part of this process.

Or this is the nudge we needed to drop BitTorrent support completely, as suggested in #19275 (closed).