feat: implement AudioClassifier

[homuler]

close #1057

[rootux]

Great Work.
Not sure what is the commented out resource manager. Heartfelt thank you for your work 🙏🏽🤘🏽

[homuler]

Not sure what is the commented out resource manager.

That doesn't matter much.
The current ResourceManager cannot be initialized twice, so only 1 test class can initialize it, which was inconvenient here.

MediaPipeUnityPlugin/Packages/com.github.homuler.mediapipe/Runtime/Scripts/Util/ResourceManager.cs

Line 36 in 3753fdf

throw new InvalidOperationException("ResourceManager can be initialized only once");