JSON Metrics output

[apeltzer]

I'd love to write a MultiQC module for this, but in order to facilitate this, would it be possible to write outputs in a JSON format for easier parsing?

e.g. FASTP does this, so we can directly load the metrics to show them in a MultiQC report. I'm working on a small validator workflow that includes fq_lint and it works nicely, but making the metrics directly accessible in a larger table would be really cool.

https://github.com/MultiQC/MultiQC/blob/main/multiqc/modules/fastp/fastp.py as an example how the JSON could look like.

https://github.com/MultiQC/test-data/tree/main/data/modules/fastp

Not too familiar with rust, otherwise I'd have opened a PR already ;-)