feat(exg pkg binary file support)

[scottrp]

Support for binary file option with exchange package exchangedata block. In order to support this the column headers for the cellid data (layer, row, column) are renamed in the binary file header to make the unique. Unique column header names are generated by adding the cellid field name ( or ) as a prefix to the , , , names. For example, originally column header for layers was just "layer". Flopy changes this column header to "cellidm1_layer" for and "cellidm2_layer" for .

[codecov]

Codecov Report

Attention: Patch coverage is 89.70588% with 7 lines in your changes missing coverage. Please review.

Project coverage is 66.3%. Comparing base (029a4e1) to head (db52879).
Report is 30 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #2205     +/-   ##
=========================================
- Coverage     68.3%   66.3%   -2.1%     
=========================================
  Files          260     294     +34     
  Lines        57947   58856    +909     
=========================================
- Hits         39611   39031    -580     
- Misses       18336   19825   +1489     

Files	Coverage Δ
flopy/mf6/coordinates/modeldimensions.py	74.4% <100.0%> (+0.9%)	⬆️
flopy/mf6/data/mfdatastorage.py	67.3% <100.0%> (-0.2%)	⬇️
flopy/mf6/data/mffileaccess.py	71.0% <92.3%> (+0.1%)	⬆️
flopy/mf6/data/mfdataplist.py	71.3% <81.4%> (-0.9%)	⬇️

... and 83 files with indirect coverage changes

[mjreno]

@scottrp this looks good to me.