Submitting a mega-PR for the CSV-related data structures

[alexdewar]

Thinking about it, I'm wondering if the best approach to getting the input file-related code merged is to write all the boilerplate code upfront (it'll mostly just be data structures) and submit it as one or more large PRs. There's already a functional test to check that reading in the settings via settings.toml works, which should catch obvious type mismatches etc. Most of it could probably be generated from a Python script. This way, we can spend more time working on and reviewing code to check and reshape the input data, without all that extra fluff in PRs.

What do you think @dalonsoa?

[alexdewar]

I think this is basically done, so I'll close the discussion.