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[bot]]

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

```diff @@ 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](https://app.codecov.io/gh/modflowpy/flopy/pull/2205?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy) | Coverage Δ | | |---|---|---| | [flopy/mf6/coordinates/modeldimensions.py](https://app.codecov.io/gh/modflowpy/flopy/pull/2205?src=pr&el=tree&filepath=flopy%2Fmf6%2Fcoordinates%2Fmodeldimensions.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy#diff-ZmxvcHkvbWY2L2Nvb3JkaW5hdGVzL21vZGVsZGltZW5zaW9ucy5weQ==) | `74.4% <100.0%> (+0.9%)` | :arrow_up: | | [flopy/mf6/data/mfdatastorage.py](https://app.codecov.io/gh/modflowpy/flopy/pull/2205?src=pr&el=tree&filepath=flopy%2Fmf6%2Fdata%2Fmfdatastorage.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy#diff-ZmxvcHkvbWY2L2RhdGEvbWZkYXRhc3RvcmFnZS5weQ==) | `67.3% <100.0%> (-0.2%)` | :arrow_down: | | [flopy/mf6/data/mffileaccess.py](https://app.codecov.io/gh/modflowpy/flopy/pull/2205?src=pr&el=tree&filepath=flopy%2Fmf6%2Fdata%2Fmffileaccess.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy#diff-ZmxvcHkvbWY2L2RhdGEvbWZmaWxlYWNjZXNzLnB5) | `71.0% <92.3%> (+0.1%)` | :arrow_up: | | [flopy/mf6/data/mfdataplist.py](https://app.codecov.io/gh/modflowpy/flopy/pull/2205?src=pr&el=tree&filepath=flopy%2Fmf6%2Fdata%2Fmfdataplist.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy#diff-ZmxvcHkvbWY2L2RhdGEvbWZkYXRhcGxpc3QucHk=) | `71.3% <81.4%> (-0.9%)` | :arrow_down: | ... and [83 files with indirect coverage changes](https://app.codecov.io/gh/modflowpy/flopy/pull/2205/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=modflowpy)