#Support additional protocols

As mentioned in the README, I'd add like to add support for more URI schemes to HURL. Here I'll list how I might implement them:

#ftp(s):

Network.FTP.Conduit.createSource looked convenient, but will likely be incompatible with dependency versions.

Network.FTP.Client.retr, .withFTP(S), & possibly .login looks almost as easy. Though I now that I tried it, I faced the same issues. Help updating this package will be appreciated.

#magnet:

There's a bittorrent package, but it appears to be unmaintained and not up to scratch for my needs.

#gopher:

Would need more conversion effort, to extract from the URL and convert them to MIMEtypes. And if we want decent audio output, those would need to be parsed according to sometimes undefined standards.

But should be easily implementable using the same APIs as for Gemini!