WIP Add optional TaskStatus for StateDescriptor callbacks

[lroberts36]

PR Summary

This PR allows for functions like FillDerived to optionally return a TaskStatus.

PR Checklist

• Code passes cpplint
• New features are documented.
• Adds a test for any bugs fixed. Adds tests for new features.
• Code is formatted
• Changes are summarized in CHANGELOG.md
• Change is breaking (API, behavior, ...)
  • Change is additionally added to CHANGELOG.md in the breaking section
  • PR is marked as breaking
  • Short summary API changes at the top of the PR (plus optionally with an automated update/fix script)
• CI has been triggered on Darwin for performance regression tests.
• Docs build
• (@lanl.gov employees) Update copyright on changed files

[Yurlungur]

looks like tests are failing... is this ready for review? Also thanks for just going ahead and doing this!

[lroberts36]

looks like tests are failing... is this ready for review? Also thanks for just going ahead and doing this!

I think the failure was due to my linter not agreeing with the github linter, hopefully fixed now. Tests are passing on Darwin.

It is ready for review, but I think @swjones is going to test and see if it works for him before it goes in.

[pgrete]

@swjones could you please remove WIP again once you tested the functionality