PSF data model

[jemorrison]

Supports JP-251
Resolves RCAL-nnnn

This PR adds a PSF reference data model to support PSF-based extraction in the JWST pipeline.

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 jwst regression tests with this branch installed ("git+https://github.com/<fork>/stdatamodels@<branch>")

news fragment change types...

• changes/<PR#>.feature.rst: new feature
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.doc.rst: documentation change
• changes/<PR#>.removal.rst: deprecation or removal of public API
• changes/<PR#>.misc.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.55%. Comparing base (fd6be8d) to head (dbfad48).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #336      +/-   ##
==========================================
+ Coverage   66.55%   67.55%   +1.00%     
==========================================
  Files         102      115      +13     
  Lines        5456     5920     +464     
==========================================
+ Hits         3631     3999     +368     
- Misses       1825     1921      +96     

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