Convert file output and constants to Python

[timothy-nunn]

To avoid merge conflicts and because so little remains, this PR will convert the remaining core (output file handling) to Python. It will also convert global_variables and constants to Python, because these depended on the output conversion.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 78.71854% with 93 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.87%. Comparing base (f71d71b) to head (be3842e).

Files with missing lines	Patch %	Lines
process/scan.py	4.54%	42 Missing ⚠️
process/process_output.py	75.36%	17 Missing ⚠️
process/final.py	25.00%	9 Missing ⚠️
process/caller.py	20.00%	4 Missing ⚠️
process/fusion_reactions.py	55.55%	4 Missing ⚠️
process/init.py	75.00%	3 Missing ⚠️
process/pfcoil.py	62.50%	3 Missing ⚠️
process/physics.py	75.00%	3 Missing ⚠️
process/tf_coil.py	78.57%	3 Missing ⚠️
process/current_drive.py	77.77%	2 Missing ⚠️
... and 2 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3811      +/-   ##
==========================================
+ Coverage   46.49%   46.87%   +0.38%     
==========================================
  Files         120      122       +2     
  Lines       27308    27515     +207     
==========================================
+ Hits        12697    12899     +202     
- Misses      14611    14616       +5     

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