Add opacties data reader for h minus ions

[light2802]

:pencil: Description

Type: :rocket: feature

Add reader for parsing H minus opacities data files [1].

:pushpin: Resources

[1] Reference opacities data

:vertical_traffic_light: Testing

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:ballot_box_with_check: Checklist

• [ ] I requested two reviewers for this pull request
• [ ] I updated the documentation according to my changes
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[codecov[bot]]

Codecov Report

Merging #351 (c679ba5) into master (275c383) will decrease coverage by 7.29%. Report is 48 commits behind head on master. The diff coverage is 48.15%.

:exclamation: Current head c679ba5 differs from pull request most recent head 8ec5017. Consider uploading reports for the commit 8ec5017 to get more accurate results

@@            Coverage Diff             @@
##           master     #351      +/-   ##
==========================================
- Coverage   74.44%   67.15%   -7.29%     
==========================================
  Files          23       30       +7     
  Lines        2614     3544     +930     
==========================================
+ Hits         1946     2380     +434     
- Misses        668     1164     +496     

Files Changed	Coverage Δ
carsus/io/chianti_/chianti_.py	85.80% <0.00%> (+19.36%)	:arrow_up:
carsus/io/nndc/base.py	0.00% <0.00%> (ø)
carsus/io/nndc/ensdf.py	0.00% <0.00%> (ø)
carsus/io/nndc/parsers.py	0.00% <0.00%> (ø)
carsus/io/opacities/opacities.py	0.00% <0.00%> (ø)
carsus/io/output/base.py	9.02% <7.61%> (-1.82%)	:arrow_down:
carsus/io/atom_data_compare.py	12.97% <12.97%> (ø)
carsus/io/zeta.py	27.65% <16.66%> (-2.35%)	:arrow_down:
carsus/io/nuclear/nndc.py	84.61% <84.61%> (ø)
carsus/io/cmfgen/base.py	87.14% <85.49%> (+3.14%)	:arrow_up:
... and 5 more

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[andrewfullard]

Tests would be great

[jvshields]

I think that generally h_minus is not a good name for a data structure/reader, and also we should go back to the source of the h_minus_cross_section_wbr.dat file and carry that along here. I believe that this comes from bell_free-free_1980 in the stardis documentation, but if the reader is specific to this source then we should mention it at such. Alternatively, if this is a generic h minus ion reader (which is preferable), then many parts of the documentation need to be changed to not specify the h_minus_cross_section file by name (i.e., line 69 in opacities.py)

[andrewfullard]

@jvshields is this going to be used for stardis? Does it need much more work?