Split flows.json file for easier diffs

This has been requested many times:

One promising (and simple) solution would be to support YAML format (as Nick says in the first link) but unfortunately, as of writing, no one has picked this up.

An option that would make diffs a little easier would be to enable the flowFilePretty flag in settings.js. This will make JSON props much easier to compare (but function code will still be escaped unlike an equivalent YAML file format)