feat: audio mixer

[giangndm]

Pull Request

Description

This PR implement audio mixer with mix-minus technique in 2 mode

• [x] Auto: all audio sources will be mix into 3 outputs. We do it with distributed style where each server shares mix-outputs of each server for avoiding overload single server. Image we have 1000 users in 2 servers, each server only sends 3 audio stream to each other instead of 500.
• [x] Manual mode: user chose which audio track it interested in. This mode is useful with some spatial audio application.

Related Issue

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Checklist

• [x] I have tested the changes locally.
• [x] I have reviewed the code changes.
• [ ] I have updated the documentation, if necessary.
• [x] I have added appropriate tests, if applicable.

Screenshots

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Additional Notes

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 70.22857% with 521 lines in your changes missing coverage. Please review.

Project coverage is 45.05%. Comparing base (7075878) to head (a90bdc4).

Files	Patch %	Lines
packages/transport_webrtc/src/transport/webrtc.rs	31.46%	122 Missing :warning:
...ackages/media_core/src/cluster/room/audio_mixer.rs	31.84%	107 Missing :warning:
...ackages/media_core/src/cluster/room/media_track.rs	22.72%	51 Missing :warning:
packages/media_core/src/cluster/room.rs	69.32%	50 Missing :warning:
packages/media_core/src/endpoint/internal.rs	38.98%	36 Missing :warning:
packages/protocol/src/protobuf/features.mixer.rs	0.00%	25 Missing :warning:
.../media_core/src/cluster/room/audio_mixer/manual.rs	85.25%	23 Missing :warning:
packages/media_runner/src/worker.rs	0.00%	17 Missing :warning:
...es/media_core/src/endpoint/internal/local_track.rs	0.00%	16 Missing :warning:
...dia_core/src/cluster/room/audio_mixer/publisher.rs	92.05%	12 Missing :warning:
... and 14 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #306 +/- ## ========================================== + Coverage 41.66% 45.05% +3.39% ========================================== Files 86 95 +9 Lines 9151 10360 +1209 ========================================== + Hits 3813 4668 +855 - Misses 5338 5692 +354 ```

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