Refactor of Supplemental Precipitation Mod (suppPrecipMod.py)

[mdeshotel]

This PR is a refactor of suppPrecipMod.py that mimics the refactor that was done for forcingInputMod.py.

Additions

Removals

Changes

-Refactor suppPrecipMod.py to mimic the refactor that was done for forcingInputMod.py.

Testing

Screenshots

Notes

Todos

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Visually tested in supported browsers and devices (see checklist below 👇)
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Testing checklist

Target Environment support

• Linux

[mxkpp]

Reviewed logic paths to confirm original behavior is equivalent to new behavior. Added some fixes as shown in commits. Rebased against development.

[mxkpp]

All ngen-forcing pytests are passing (with tolerance) from the nwm-rte Dev Container:

( cd src/ngen-forcing && pytest )
( cd src/ngen-forcing && mpirun -n 2 pytest )

@idtodd I needed to make significant changes. This is ready for your review.

[mxkpp]

Merging to the new refactor branch which was branched off from development today.