JP-3768: Move outlier detection median computers to stcal

[emolter]

Resolves JP-3768

This PR ports the median calculation machinery added by spacetelescope/jwst#8782 into stcal for use by other missions. See spacetelescope/jwst#8840 for the related changes in 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/<PR#>.apichange.rst: change to public API
• changes/<PR#>.bugfix.rst: fixes an issue
• changes/<PR#>.general.rst: infrastructure or miscellaneous change

[codecov]

Codecov Report

Attention: Patch coverage is 99.26740% with 2 lines in your changes missing coverage. Please review.

Project coverage is 85.21%. Comparing base (8988d2c) to head (d41546a).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/stcal/outlier_detection/median.py	98.68%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #292      +/-   ##
==========================================
+ Coverage   84.76%   85.21%   +0.44%     
==========================================
  Files          44       46       +2     
  Lines        8542     8815     +273     
==========================================
+ Hits         7241     7512     +271     
- Misses       1301     1303       +2     

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[emolter]

jwst regtests started here
edit: no failures