Setting threshold values in post-processor with data

[ym-han]

This is motivated by some feedback from Andreas about how it is currently hard for users to figure out how to manually set the threshold values in the Parrot post-processor (and I agree with him).

Dhruv Jain 2022's system ("Nonverbal Sound Detection for Disordered Speech") sets the threshold values in their post-processor by finding the threshold values that optimize certain metrics, on a per-class basis:

This would be simple to implement for Parrot once we implement / expose the metrics we're interested in, and I definitely want to try implementing this.

[chaosparrot]

I am currently working on some post-processing recording improvements, I'll try and see if I implement some of the ideas given inside that paper :)