Please welcome Torsten Zühlsdorff (tz@) as a new ports committer!

Torsten has contributed far too many PRs going back to 2013 and has recently
finished the long-standing project of bringing Gitlab to the the ports tree.
It's time for Torsten make some commits of his own.

junovitch, pi, and swills are the mentors

While here, sort mentors file by mentee login name.

Approved by: portmgr (implicit)