Remove Mediainfo Dependency

[joncameron]

Description

Mediainfo has been removed as a dependency in Avalon, but Active Encode still relies on it. This issue is for making the switch here as well to use only FFmpeg for reporting on media information in files.

Done Looks Like

• mediainfo calls replaced with ffprobe calls for media querying

[elynema]

Related to #6147, Mason investigated the idea of flipping from mediainfo to ffmpeg in active-encode to prevent the need to convert between 2 different ISO standards for caption files as imported from the mp4 container vs. stored in MCO.

It does look like ffprobe uses the 3 letter language codes [that Avalon uses for language storage], however the XML output from ffprobe is vastly different than mediainfo's. Names are different, how streams/tracks are represented in the XML are different, etc. Doing the changeover is going to require some discussion and planning, I think.
So for now, I'm going to continue looking at iso 639-1 to iso 639-2 conversion as I think that will be much more straightforward.