Improve support of BitTorrent links in chats

[tehnick]

Currently BitTorrent magnet link in AirDC++ WebUI 2.11.0 looks like:

As you see, such link is not parsed as magnet link and is showed as a whole.

Please use human readable representation of BitTorrent magnet links. They follow the same magnet URI scheme as magnet links for DC and may be parsed in the same way.

For example, the same magnet links in EiskaltDC++ 2.4.1 look like:

EiskaltDC++ does not have support of BitTorrent protocol and opens such links in external application which is registered as BiTorrent client in the system. And this is normal behavior which is expected from DC client.

In FlylinkDC++ r6xx BitTorrent magnet links look the same way:

But FlylinkDC++ has embedded support of BitTorrent protocol and it opens links inside itself.

[tehnick]

You may use this text for tests:

magnet link with TTH: magnet:?xt=urn:tree:tiger:NKPIKQPJW45WYQ7AGEGIZ4JA4PBAJQWY2H4SBTY&xl=12836491531&dn=Tears+of+Steel+(2012).mkv
BitTorrent magnet link: magnet:?xt=urn:btih:e116804725f2c6cfda4fd0fe3e31c4c9457dad98&dn=debian-live-10.7.0-amd64-kde%2bnonfree.iso&tr=http%3a%2f%2fbttracker.debian.org%3a6969%2fannounce
Search magnet link: magnet:?kt=EiskaltDC%2B%2B+2.4.1&dn=EiskaltDC%2B%2B+2.4.1