Refactor Model: Extract ModelStateDerived

[dweindl]

... to slim down amici::Model

[codecov]

Codecov Report

Merging #1399 (936da87) into develop (8f7ef5c) will decrease coverage by 0.32%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1399      +/-   ##
===========================================
- Coverage    76.61%   76.28%   -0.33%     
===========================================
  Files           22       22              
  Lines         3181     3799     +618     
===========================================
+ Hits          2437     2898     +461     
- Misses         744      901     +157     

Flag	Coverage Δ
petab	69.50% <ø> (ø)

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Impacted Files	Coverage Δ
python/amici/ode_export.py	86.43% <0.00%> (-5.87%)	⬇️
python/amici/sbml_import.py	89.12% <0.00%> (-4.45%)	⬇️

[sonarcloud]

SonarCloud Quality Gate failed.

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

0.0% Coverage
2.0% Duplication