Updating stream object to support multichannel audio

[stevenrick]

Currently the application only records a single channel of audio per stream (whether or not video is present and whether or not the device supports more than one channel)

In order to produce more lossless data we should update the way we handle audio constraints to record all available channels (or give the user the ability to record all available channels?)

To verify this can hardcode channelCount: 2, into constraints and will update recording to stereo if supported

Our solution should be device capability aware - so can use something like
var microphone = this.#audioContext.createMediaStreamSource(stream); and then microphone.channelCount); in monitorAudio() to get the reported number of channels available.

More information on web audio api documentation available at MDN

[stevenrick]

Adding more details here after exploring with a multichannel (more than 2) audio input device. It seems the basic mediaDevice objects supported by Chrome / Node.js only supports exposing 2-channels. It seems the best route forward would be using something like naudiodon which is a cross-platform library for accessing PortAudio

[stevenrick]

closing #51 because this can address it in parallel
link to old code using naudiodon