Bring the compatibility methods from AudioDriverWASAPI into AudioDriver

[kus04e4ek]

Describe the project you are working on

Oboe AudioDriver

Describe the problem or limitation you are having in your project

Achieving the least possible latency and not wasting too much space on avoidable allocations is kinda impossible without writing the compatibility methods that would transform data from device's format to Godot's format or the other way around.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

All of these methods are already written in AudioDriverWASAPI:

• Downmixing output;
• Handling arbitrary amount of input channels;
• Arbitrary device audio format.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

It's just pretty much copy-paste process.

If this enhancement will not be used often, can it be worked around with a few lines of script?

Can't be codded in a few lines of script and will just repeat already written code.

Is there a reason why this should be core and not an add-on in the asset library?

Can't be add-on.