HES Workflow Generator, try 2

[nmerket]

Pull Request Description

This ports over the changes from #252 into a later version of buildstockbatch, replacing that PR.

Checklist

Not all may apply

• Code changes (must work)
• Tests exercising your feature/bug fix (check coverage report on Checks -> BuildStockBatch Tests -> Artifacts)
• Coverage has increased or at least not decreased. Update minimum_coverage in .github/workflows/ci.yml as necessary.
• All other unit and integration tests passing
• Update validation for project config yaml file changes
• Update existing documentation
• Run a small batch run on Eagle to make sure it all works if you made changes that will affect Eagle
• Add to the changelog_dev.rst file and propose migration text in the pull request

[nmerket]

@rajeee I'm a little lost on what happened with the refactor in #456. I just tried to pull in the latest from develop and am having trouble. In this PR, I have a workflow generator that inserts the argument os_hescore_directory into BuildExistingModel. I used to just put it in the workflow arguments in the yaml, but that doesn't seem to be working now. What's the right way to go about that at this point?

[rajeee]

@rajeee I'm a little lost on what happened with the refactor in #456. I just tried to pull in the latest from develop and am having trouble. In this PR, I have a workflow generator that inserts the argument os_hescore_directory into BuildExistingModel. I used to just put it in the workflow arguments in the yaml, but that doesn't seem to be working now. What's the right way to go about that at this point?

Looks like I introduced a bug in that PR that wasn't caught by the test.
This line causes crash if you don't have BuildExistingKey already present. Bug fix would be to check if that key exists first, and if not, initialize with empty dict.