feat(simulation+model options): Dynamically generate simulation options from simulation namefile dfn

[spaulins-usgs]

Simulation and model file initialization parameters and attributes are now dynamically generated to include the namefile options found in the dfn file.

[codecov]

Codecov Report

Merging #1842 (5ad8b9e) into develop (0e13703) will decrease coverage by 1.9%.
The diff coverage is 56.8%.

@@            Coverage Diff            @@
##           develop   #1842     +/-   ##
=========================================
- Coverage     72.2%   70.4%   -1.9%     
=========================================
  Files          256     257      +1     
  Lines        56112   56206     +94     
=========================================
- Hits         40564   39600    -964     
- Misses       15548   16606   +1058     

Impacted Files	Coverage Δ
flopy/mf6/data/mfdatalist.py	70.5% <0.0%> (-1.8%)	⬇️
flopy/mf6/modflow/mfgwf.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwt.py	100.0% <ø> (ø)
flopy/mf6/utils/generate_classes.py	17.3% <0.0%> (ø)
flopy/mf6/utils/createpackages.py	6.7% <2.1%> (-0.4%)	⬇️
flopy/mf6/data/mfdatautil.py	52.1% <31.2%> (-2.2%)	⬇️
flopy/mf6/data/mfdatascalar.py	58.9% <50.0%> (-1.6%)	⬇️
flopy/mf6/mfmodel.py	56.7% <53.3%> (-2.4%)	⬇️
flopy/mf6/mfsimbase.py	59.8% <59.8%> (ø)
flopy/mf6/modflow/mfsimulation.py	100.0% <100.0%> (+34.3%)	⬆️

... and 50 files with indirect coverage changes