rtmp: support additional Enhanced-RTMP features (#3685)

[aler9]

Fixes #3685

TODO

• publish Opus tracks
• [ ] read Opus tracks
• proxy Opus tracks
• publish AC-3 tracks
• [ ] read AC-3 tracks
• proxy AC-3 tracks
• publish multiple video tracks
• publish multiple audio tracks
• tests

[codecov]

Codecov Report

Attention: Patch coverage is 61.38996% with 400 lines in your changes missing coverage. Please review.

Project coverage is 56.02%. Comparing base (f216043) to head (f32f28b).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/protocols/rtmp/reader.go	43.19%	207 Missing and 31 partials ⚠️
internal/protocols/rtmp/to_stream.go	0.00%	105 Missing and 1 partial ⚠️
...tocols/rtmp/message/msg_video_ex_sequence_start.go	67.85%	18 Missing and 9 partials ⚠️
...tocols/rtmp/message/msg_audio_ex_sequence_start.go	84.74%	6 Missing and 3 partials ⚠️
.../protocols/rtmp/message/msg_video_ex_multitrack.go	91.07%	4 Missing and 1 partial ⚠️
...s/rtmp/message/msg_audio_ex_multichannel_config.go	95.31%	3 Missing ⚠️
.../protocols/rtmp/message/msg_audio_ex_multitrack.go	94.64%	2 Missing and 1 partial ⚠️
internal/protocols/rtmp/message/opus_id_header.go	93.18%	2 Missing and 1 partial ⚠️
...rotocols/rtmp/message/msg_video_ex_sequence_end.go	81.81%	2 Missing ⚠️
internal/protocols/rtmp/message/reader.go	94.44%	1 Missing and 1 partial ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4088      +/-   ##
==========================================
+ Coverage   55.60%   56.02%   +0.42%     
==========================================
  Files         193      199       +6     
  Lines       19851    20425     +574     
==========================================
+ Hits        11038    11444     +406     
- Misses       7965     8121     +156     
- Partials      848      860      +12     

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[github-actions]

This issue is mentioned in release v1.11.0 🚀
Check out the entire changelog by clicking here