feat(GeoDataFrame support): geopandas support for shapefile exporting

[jlarsen-usgs]

This PR supersedes the draft PR #2573 and continues the cleanup of legacy shapefile exporting code and integration of geopandas GeoDataFrame support.

[codecov]

Codecov Report

❌ Patch coverage is 56.47208% with 343 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.3%. Comparing base (556c088) to head (f0e9211).
⚠️ Report is 99 commits behind head on develop.

Files with missing lines	Patch %	Lines
flopy/export/shapefile_utils.py	41.2%	47 Missing ⚠️
flopy/plot/plotutil.py	2.5%	38 Missing ⚠️
flopy/mf6/data/mfdatalist.py	40.9%	36 Missing ⚠️
flopy/mf6/data/mfdataplist.py	50.0%	30 Missing ⚠️
flopy/utils/binaryfile/__init__.py	7.4%	25 Missing ⚠️
flopy/modflow/mfsfr2.py	54.7%	24 Missing ⚠️
flopy/mf6/data/mfdataarray.py	65.1%	23 Missing ⚠️
flopy/utils/datafile.py	32.0%	17 Missing ⚠️
flopy/mf6/mfpackage.py	48.3%	16 Missing ⚠️
flopy/utils/util_array.py	68.0%	16 Missing ⚠️
... and 11 more

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2671      +/-   ##
===========================================
+ Coverage     55.5%    72.3%   +16.7%     
===========================================
  Files          644      667      +23     
  Lines       124135   130272    +6137     
===========================================
+ Hits         68947    94231   +25284     
+ Misses       55188    36041   -19147     

Files with missing lines	Coverage Δ
flopy/discretization/grid.py	74.3% <100.0%> (-1.7%)	⬇️
flopy/mf6/data/mfdatautil.py	60.6% <100.0%> (-17.3%)	⬇️
flopy/utils/geospatial_utils.py	92.7% <100.0%> (-0.4%)	⬇️
flopy/utils/gridgen.py	75.8% <100.0%> (-11.3%)	⬇️
flopy/mf6/mfmodel.py	57.5% <88.2%> (-23.4%)	⬇️
flopy/discretization/structuredgrid.py	53.2% <72.7%> (+5.7%)	⬆️
flopy/mbase.py	70.2% <82.3%> (-2.6%)	⬇️
flopy/utils/particletrackfile.py	95.6% <94.8%> (-0.4%)	⬇️
flopy/discretization/unstructuredgrid.py	75.9% <66.6%> (-5.6%)	⬇️
flopy/pakbase.py	82.4% <73.6%> (-2.0%)	⬇️
... and 15 more

... and 536 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[jlarsen-usgs]

@wpbonelli it looks like the smoke tests are failing on test_mf2005_copy and also failed on the prior commit to FloPy. I can't currently reproduce the error on Windows. Any insight into what might be causing this?