Mkaing coolprops optional

[shimwell]

modernizing the setup by moving to setup.cfg, pyproject.toml and duplicating using the example made by plasmafair

TODO
find a way of testing on python 3.9 or change docker image to use python 3.8

[shimwell]

Looks like a reoccurring hdf5 error is happening, I think this requires a numpy or h5py update, but seeings as openmc 0.13 is nearly hear I think we can wait and see if the new openmc version helps

[codecov]

Codecov Report

Merging #16 (d535d16) into develop (48c85b9) will decrease coverage by 1.03%.
The diff coverage is 64.91%.

@@             Coverage Diff             @@
##           develop      #16      +/-   ##
===========================================
- Coverage    90.86%   89.82%   -1.04%     
===========================================
  Files            3        3              
  Lines          558      570      +12     
===========================================
+ Hits           507      512       +5     
- Misses          51       58       +7     

Impacted Files	Coverage Δ
neutronics_material_maker/__init__.py	79.16% <50.00%> (-20.84%)	⬇️
neutronics_material_maker/utils.py	82.99% <58.62%> (ø)
neutronics_material_maker/material.py	92.98% <83.33%> (-0.47%)	⬇️

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