[chore][CICD] More reusable workflow organization

[crobert-1]

Description:

Summary of changes:

1. Move reusable workflows to have their filenames prefixed with reusable- to make reusable workflows easier to find, and more obvious which workflows are top-level caller workflows, and which are the called workflows. The original goal was to have them all under the workflow subdirectory .github/workflows/reusable/ but this is not a supported feature of GitHub yet: https://github.com/orgs/community/discussions/10773.
2. Update chef-test workflow to use reusable functionality. Chef tests were updated in parallel with reusable workflows, so it wasn't updated as a part of the original PRs.
3. Clean up some more cross-compile and setup-environment references that had been missed previously.
4. Remove unused GO_VERSION env variables
5. Remove PIP_CACHE input variable since it doesn't change based on caller.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.94%. Comparing base (178d920) to head (2dacfcc).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6356   +/-   ##
=======================================
  Coverage   44.93%   44.94%           
=======================================
  Files         390      390           
  Lines       27010    27010           
=======================================
+ Hits        12137    12139    +2     
+ Misses      14006    14004    -2     
  Partials      867      867           

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