Pull common parts of skymatch from romancal and jwst into stcal

[WilliamJamieson]

This PR pulls the common parts of skymatch from romancal and jwst into stcal to be shared.

Note, no tests are included because it is well tested by the step tests in both romancal and jwst.

Tasks

• [ ] update or add relevant tests
• [ ] update relevant docstrings and / or docs/ page
• [ ] Does this PR change any API used downstream? (if not, label with no-changelog-entry-needed)
  • [ ] write news fragment(s) in changes/: echo "changed something" > changes/<PR#>.<changetype>.rst (see below for change types)
  • [ ] run regression tests with this branch installed ("git+https://github.com/<fork>/stcal@<branch>")
  • [ ] jwst regression test
  • [ ] romancal regression test

news fragment change types...

- ``changes/.apichange.rst``: change to public API - ``changes/.bugfix.rst``: fixes an issue - ``changes/.general.rst``: infrastructure or miscellaneous change

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 74.07407% with 329 lines in your changes missing coverage. Please review.

Project coverage is 84.71%. Comparing base (60bd3b8) to head (3f3832b). Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/stcal/skymatch/skyimage.py	61.09%	270 Missing :warning:
src/stcal/skymatch/region.py	85.13%	40 Missing :warning:
src/stcal/skymatch/skymatch.py	92.40%	19 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #310 +/- ## ========================================== - Coverage 86.21% 84.71% -1.51% ========================================== Files 47 54 +7 Lines 8812 10177 +1365 ========================================== + Hits 7597 8621 +1024 - Misses 1215 1556 +341 ```

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