use OpenAstronomy workflows and move MacOS jobs to schedule

[zacharyburnett]

This PR abstracts CI workflows to the OpenAstronomy workflows; this should reduce maintenance for updating and maintaining actions. Additionally, these changes move the majority of MacOS jobs to the weekly scheduled workflow. This should alleviate the issue where the limited MacOS runners for the organization are not available for CI jobs.

Checklist for maintainers

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• Make sure the JIRA ticket is resolved properly

[nden]

Tests are not running.

[zacharyburnett]

Tests are not running.

It looks like the OpenAstronomy workflow creates a set_env.py file that is not properly cleaned up, so pytest finds it and encounters an error when executing it. I made a PR to attempt to resolve the issue: OpenAstronomy/github-actions-workflows#116

[zacharyburnett]

tests are running now. Required status names in the branch protection rules will have to be updated upon merge.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (78941d9) 77.61% compared to head (a4ef95b) 77.61%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7498   +/-   ##
=======================================
  Coverage   77.61%   77.61%           
=======================================
  Files         452      452           
  Lines       36193    36193           
=======================================
  Hits        28091    28091           
  Misses       8102     8102           

Flag	Coverage Δ		*Carryforward flag
nightly	77.60% <ø> (ø)		Carriedforward from 78941d9
unit	?

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[zacharyburnett]

The CRDS cache is incorrect because test-opencv-xdist completes before the full tests; this should be resolved by #7499 which removes the separate testing

EDIT: resolved