[api] Add cost surface piece exporter and importer [MRXN23-111] [MRXN23-19] [MRXN23-112] [MRXN23-20]

[yulia-bel]

Add cost surface piece exporter

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Checklist before submitting

• Meaningful commits and code rebased on develop.
• If this PR adds feature that should be tested for regressions when
  deploying to staging/production, please add brief testing instructions
  to the deploy checklist (docs/deployment-checklist.md)
• Update CHANGELOG file

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Name	Status	Preview	Comments	Updated (UTC)
marxan	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Oct 5, 2023 11:39am

[hotzevzl]

@yulia-bel thanks, and apologies for taking so long to review this - I've been mostly down the rabbit hole of trying to make the functionality of this feature to work in practice in a variety of contexts (projects with or without scenarios, with run scenarios, etc.) and as you know this has been a royal headache in its own right because of the moving pieces in related PRs 😬

As it stands, the code itself looks fine, but:

• please rebase it on the latest develop and consider what to do with the check that I highlighted inline in my review, as after rebasing we'd be "guaranteed" (except if any bugs, etc) that by the time we clone a project, this would have at least the default cost surface
• check the functionality after rebasing - so far I have only been able to get cloning to work with a very specific combination of factors

[hotzevzl]

I wonder if we should just give up in case we don't have any cost surfaces, or even skip this check and go ahead (in which case we'd have an empty fileContent later on.

In practice, once rebasing this PR on the latest develop, we should never have projects without any cost surface (at least the default one must be created for the project to be ready). I don't think we should necessarily check here if a is ready/well formed, because we have these checks in place elsewhere and we should not be able to even clone a project if the project is not fully ready.

On the other hand, if we did not care here (basically avoiding altogether the if (costSurfacesIds.length > 0) check), we'd have a malformed export that should fail on import (garbage in, garbage out).

But, with the current implementation, more or less we end up with some kind of inconsistent state if costSurfacesIds.length === 0, so I am not sure. I'd err on avoiding the check altogether, and maybe logging an error. Or making the export fail altogether.

[hotzevzl]

just a note on style - my recommendation for these kinds of "augmentations" is to use named functions to make what we're doing via array operations (filter, map, etc.), spreads and so on clearer.

In practice here we're combining a lookup of cost surface costs with the setter part of a lens, using lower-level primitives: which is ok and works, but makes even a tiny snippet of code like this less legible than something like const fileContent: ProjectCostSurfacesContent = addCostDataToCostSurfaces(costSurfaces, costSurfaceCostData)

but no need to do anything here! (and as always, these kinds of style comments can be highly opinable)