Draft: demux: mkv: add support for ZSTD decompression
It will be part of Matroska v5 once the Pull Request 1 is merged.
This code also serves as a Proof Of Concept for the approval of zstd in Matroska.
Dictionary is not supported supported yet, which is the same as with the other compression methods that can also have a dictionary.
Edited by Steve Lhomme