net/mkvserver_mk2: import mkvserver_mk2-0.0.0.20200117

Matroska Server Mk2

This project is the result of years of thinking, trying and finally
succeeding.

This software makes it possible to stream (almost) anything remuxed
as matroska live in real-time over http to multiple clients.

This is probably also one of the first real world usages of FFmpeg's
http server component (which I wrote as part of GSoC 2015).

(ryoon)