Add validation for SVD commodities

[TinyMarsh]

Description

Adds validation for SVD commodities by checking that for every commodity of "SVD" type, there is at least one process that can produce the commodity. Also extended this to check for every region and year and time slice, where SVD is > 0, that there is a process defined that can meet demand.

Fixes #168

Type of change

• Bug fix (non-breaking change to fix an issue)
• New feature (non-breaking change to add functionality)
• Refactoring (non-breaking, non-functional change to improve maintainability)
• Optimization (non-breaking change to speed up the code)
• Breaking change (whatever its nature)
• Documentation (improve or add documentation)

Key checklist

• All tests pass: $ cargo test
• The documentation builds and looks OK: $ cargo doc

Further checks

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Attention: Patch coverage is 95.31250% with 6 lines in your changes missing coverage. Please review.

Project coverage is 95.60%. Comparing base (54e9a7f) to head (2bac877).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
src/input/process.rs	96.03%	2 Missing and 3 partials ⚠️
src/commodity.rs	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #381      +/-   ##
==========================================
+ Coverage   95.58%   95.60%   +0.02%     
==========================================
  Files          31       31              
  Lines        4121     4235     +114     
  Branches     4121     4235     +114     
==========================================
+ Hits         3939     4049     +110     
- Misses         90       92       +2     
- Partials       92       94       +2     

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[tsmbland]

Looks good, but I'll let @alexdewar give the final go-ahead.

The only comment I have is that the process must also have availability > 0, otherwise even with flow > 0 it cannot produce any output. So really, I think we need to check that there's at least one process with flow * availability > 0 in every timeslice/year/region with demand

[alexdewar]

Looks good!

I hadn't thought of this, but @tsmbland's right about the availability thing: it does need an extra check that availability > 0 too. Otherwise all good 😄

[alexdewar]

Suggested change

	let regions: HashMap<Rc<str>, RegionSelection> = vec![
	let regions: HashMap<Rc<str>, RegionSelection> = [

[TinyMarsh]

Apologies for taking a while to get back to this.

To be honest I don't really understand why process availabilities are ranges, but I have included a check that the range is above zero in any case. I hope that's correct.

I had to factor out some of the arguments because Clippy wasn't happy, hence the ValidationParams struct. If this is horrible then let me know and I'll change it.

[TinyMarsh]

@alexdewar Latest commit just includes changes we went through together.

[alexdewar]

LGTM! Sorry the last part ended up being a faff....