obs-ffmpeg: Allow specifying mux settings directly

(Jim) Allows the ability to specify mux settings directly on the
output's structure itself rather than just via settings. This is useful
for network-based muxer outputs (such as HLS).
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f