Evaluate and plot symbolic expressions based on simulation results

[dweindl]

Adds functions amici.numpy.evaluate and amici.plotting.plot_expressions to evaluate or directly plot symbolic expressions of model quantities, respectively.

Demo: see end of this section https://amici--2152.org.readthedocs.build/en/2152/ExampleSteadystate.html#Plotting-trajectories

[codecov]

Codecov Report

Merging #2152 (cee7e5e) into develop (ea95896) will decrease coverage by 0.03%.
The diff coverage is 53.33%.

@@             Coverage Diff             @@
##           develop    #2152      +/-   ##
===========================================
- Coverage    76.63%   76.61%   -0.03%     
===========================================
  Files           82       82              
  Lines        14985    15000      +15     
===========================================
+ Hits         11484    11492       +8     
- Misses        3501     3508       +7     

Flag	Coverage Δ
cpp	73.53% <ø> (ø)
petab	53.82% <13.33%> (-0.11%)	⬇️
python	77.17% <53.33%> (-0.07%)	⬇️
sbmlsuite	?

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Files	Coverage Δ
python/sdist/amici/numpy.py	82.82% <100.00%> (+1.50%)	⬆️
python/sdist/amici/plotting.py	0.00% <0.00%> (ø)