IPv6 support added for tracker

We've added preliminary support for IPv6 peers in our tracker.
This is still in testing phase and not guaranteed to work as expected.
If you have IPv6 connectivity then make sure it's enabled in your clients settings.
If you're using latest version of qBt (4.2.1) then IPv6 should already be working for you. If you're using older versions then turn it on manually from settings.
Not all clients will work. Currently QBittorrent is tested and approved for IPv6.