Change fsds to fs across python & R packages

[glitt13]

Renamed all things fsds to fs (formulation-selector) in the python & R code base.
Also integrated the NWIS gage ID checker/corrector into the standard fs_proc processing

Additions

Integrated the check_nwis logic into proc_col_schema()

Removals

Changes

Testing

1. All unit tests passed corresponding to the fs_proc and fs_algo packages modified fsds to fs
2. Unit test created for the NWIS checker, check_fix_nwissite_gageids

Screenshots

Notes

Todos

• Still need to modify fsds naming in the R code, but will do so once the existing PR review is accepted to reduce merge conflicts.

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

• Windows
• Linux
• Browser

Accessibility

• Keyboard friendly
• Screen reader friendly

Other

• Is useable without CSS
• Is useable without JS
• Flexible from small to large screens
• No linting errors or warnings
• JavaScript tests are passing

[glitt13]

Note that changing fs_proc to rafts_proc will be easy - let's discuss preferred package naming.

[glitt13]

@bolotinl, note that this PR also includes a new feature: adding the pre-existing check_nwis_gage_id_fix() function to become a standard check inside proc_col_schema() when NWIS gage data are used as the gage_id. This PR also added the new unit test corresponding to check_nwis_gage_id_fix()