Multichannel files

[Gautzilla]

🐙Sup?

This PR aims at enhancing the handling of multitchannel files.

Basically, the previous iteration was really straightforward and rigid:

• AudioData associated with multichannel AudioFile systematically fetched data from every channel
• SpectroData associated with multichannel AudioData only referred to the first channel.

💡Now what?

Here's what I intend to do about it:

Feature	Detail	Dev status
AudioData.channels	List of int that specifies which channels of the audio file(s) are to get.	✅
AudioData.get_value() rework	Get only value from the channels specified in AudioData.channels	✅
SpectroData.audio_channel	Index of the channel of the linked AudioData that the SpectroData concerns	✅
Serialization	Addition of the channel properties to the data dicts	✅
AudioData.normalize() rework	Channel-wise normalization (with updated normalization_values dict)	✅
Dataset incorporations	Helpers for managing channels on AudioDataset and channel on SpectroData	❔ (is that truly necessary)
Transform incorporations	Public API support for channel selecting	❔ (this could as well been done with some Core on top of the Public, as the properties should be included in the dicts)
Documentation	Add a page in the documentation for working with multichannel audio.	❌

[coveralls]

coverage: 98.979% (+0.005%) from 98.974% — Gautzilla:multichannel-files into Project-OSmOSE:main