Move torrentfs stuff into a different repo

It's probably best to move the torrentfs stuff into another repo. It doesn't compile on Windows, and it's not core to a functioning torrent client.

I've experimented with this in https://github.com/anacrolix/torrent/tree/fs-separate-module.

Is this happening? Is there currently a way to mount magnet links?

I'm not currently working on this. I don't recall implementing mounting via magnet links, but it's trivial enough.

@smhmd take a look at btfs

@pataquets I actually expressed interest in this because btfs was hanging on occasion.

Well let me know how you go with this. It's been actively tested in the CI for years now, there's no issues with it as far as I know.

A stand-alone command that mounted a single magnet link would be pretty cool, I think the current implementation here watches a directory of torrents, and possibly a file containing magnets and exposes those in the mount dir.

@smhmd take a look at https://github.com/anacrolix/torrent/blob/master/fs/test.sh.

In the metainfo directory, specified to cmd/torrentfs, any files ending in .magnet are scanned for a magnet link per line, and those are immediately exposed in the mountdir.

See https://github.com/anacrolix/torrent/issues/688.