changing to cad_to_h5m and graveyard removal

[shimwell]

graveyard no longer needed as bounding surface is automated in openmc openmc-dev/openmc#2118

Also making use of cad-to-h5m which is simpler than the current method of producing DAGMC h5m files from cad

[codecov]

Codecov Report

Merging #282 (cf9994e) into main (15f7166) will increase coverage by 0.19%.
The diff coverage is 89.18%.

❗ Current head cf9994e differs from pull request most recent head ed243c2. Consider uploading reports for the commit ed243c2 to get more accurate results

@@            Coverage Diff             @@
##             main     #282      +/-   ##
==========================================
+ Coverage   96.30%   96.50%   +0.19%     
==========================================
  Files          82       82              
  Lines        5524     5405     -119     
==========================================
- Hits         5320     5216     -104     
+ Misses        204      189      -15     

Impacted Files	Coverage Δ
src/paramak/shape.py	96.83% <76.92%> (-0.24%)	⬇️
src/paramak/reactor.py	85.11% <94.11%> (+5.19%)	⬆️
src/paramak/__init__.py	94.56% <100.00%> (+0.05%)	⬆️
...tric_components/toroidal_field_coil_princeton_d.py	100.00% <100.00%> (ø)
src/paramak/utils.py	90.85% <100.00%> (-1.87%)	⬇️

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