Add scripts to coverage testing

[MichaelClerx]

Start on #117

Separates command line argument parsing and export_config from code in run_herg_qc

[codecov]

Codecov Report

❌ Patch coverage is 0% with 105 lines in your changes missing coverage. Please review.
✅ Project coverage is 37.79%. Comparing base (36d3eac) to head (e7125e8).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
pcpostprocess/scripts/run_herg_qc.py	0.00%	104 Missing ⚠️
pcpostprocess/scripts/__main__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #101       +/-   ##
===========================================
- Coverage   91.73%   37.79%   -53.94%     
===========================================
  Files          11       14        +3     
  Lines         871     2114     +1243     
===========================================
  Hits          799      799               
- Misses         72     1315     +1243     

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[MichaelClerx]

Verified current code produces same output as original for run_herg_qc.py