MythCoreContext: Fix bad copy/paste
Fix proxy using IPv6

Fixes #12174
Allow to override which mpegts demuxer is used

Set FFMPEGTS override (call with -O FFMPEGTS=1)

Refs:#12153
Ignore audio packets from ignored streams

Fixes #12153
Add —allaudiotracks

By default mythtranscode exclude all audio tracks where the number of channels is detected as 0. However, under some circumstances our mpegts demuxer doesn’t properly detect the audio streams and mark them as having 0 channels.
Use —allaudiotracks to include all audio tracks found.

Refs: #12153