Fixing the 4-component version of GST

[jsaffer]

The original GST paper (http://doi.org/10.1007/s11467-013-0319-7) gives a parameterization of the CR flux in several populations based on p, He, C, O and Fe and heavier mass groups (Table 3). I see that this doesn't match the 5-component model that is used in some working groups (that's why I didn't touch the 5-component model) but for the 4-component version it would be appropriate to use the correct Z values and combine C and O. Also, it is necessary to include the heavier components with Z>50 into the iron group. According to the author (Serap), the 4-population version is to be preferred, that's why I swtiched to it.
I am aware that this creates a difference between GlobalFitGST and GlobalFitGST_IT but the way it has been defined so far is simply incorrect.

[github-actions]

Test Results

    9 files  ±0      9 suites  ±0   3m 0s ⏱️ +11s
  572 tests +1    359 ✅ +1    213 💤 ±0  0 ❌ ±0 
5 148 runs  +9  3 231 ✅ +9  1 917 💤 ±0  0 ❌ ±0 

Results for commit 138a5db. ± Comparison against base commit f843047.

♻️ This comment has been updated with latest results.

[kjmeagher]

I am hesitant to change the value of models that already exist and would prefer to create a new model with a new name and mark the old model as deprecated. If the 5-comp version is similarly incorrect a correct version should also be created and the old version marked as depreciated. Since he was the original author of the 5comp model i have asked @The-Ludwig to coordinate on the correct solution.

Also not the pre-commit is failing because there was a file Level3_IC86.2012_SIBYLL2.1_p_12360_E6.0.i3.bz2 that was erroneously added to the repo. It has been deleted on main, just delete it in this branch as well. The tests are failing because there is regression test using pytest-regression. You need to run pytest --regen-all to update the regression files

[The-Ludwig]

Since he was the original author of the 5comp model i have asked @The-Ludwig to coordinate on the correct solution.

I am super interested in making this clearer and easier to use correctly, but I implented the GSF 5-component version, not the GST 5-component version. Although I would like to take credit for it, the 5-component GST model was in this repository from the initial commit and is thus likely carried over from icetray and predates my time in IceCube.

[kjmeagher]

Yes it appears i read the blame log incorrectly the original commit is from 2015 https://code.icecube.wisc.edu/projects/icecube/changeset/139164/IceCube

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (f843047) to head (138a5db).

Additional details and impacted files

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##              main       #58   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           12        12           
  Lines          841       844    +3     
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+ Hits           841       844    +3     

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