Develop post-processing functions to produce basin-level grids for NWM output products [NGWPC-10282]

[sivasankkar]

This PR includes functions developed for producing basin-level (or whatever is in the geopackage used in realization) grids usng some post-processing routines.

Additions

• output_variables/DataReader.py - class file containing functions to read the catchment output netcdf produced by ngen.
• output_variables/DataProcessor.py - class file containing functions to produce template and output basin gridded NetCDF files
• output_variables/DataReader.py - Utiliites functions for downloading NWM data from NOMADS, extracting metadata etc.
• output_variables/Readme_wip.md - A Readme file with documentation and examples for the functions.
• netcdf_production_sample.py - file with CLI functions to call the various post-processing routines

Removals

Changes

Testing

1. Tested with a couple of ngen catchment netcdf outputs. The basin-level NetCDF output file was created successfully.
2. Tested data download from NOMADS and extraction of metadata with the sample downloads.

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
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Testing checklist (automated report can be put here)

Target Environment support

• Linux