Refactor model config and convert it to pydantic

[oyvindeide]

Issue
Resolves #my_issue

Approach
Short description of the approach

(Screenshot of new behavior in GUI if applicable)

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure tests pass locally (after every commit!)

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Create Backport PR to latest release

[sondreso]

Nice! 💯

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.65%. Comparing base (2d73055) to head (15165f8).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8501      +/-   ##
==========================================
+ Coverage   90.62%   90.65%   +0.02%     
==========================================
  Files         344      344              
  Lines       20966    20979      +13     
==========================================
+ Hits        19001    19019      +18     
+ Misses       1965     1960       -5     

Flag	Coverage Δ
gui-tests	75.95% <90.69%> (+0.02%)	⬆️
integration-tests	53.93% <90.69%> (+0.04%)	⬆️
unit-tests	68.64% <100.00%> (+0.06%)	⬆️

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