Renamed unscaled to autoscaled, based on better nomenclature

[dft-dutoit]

The UnScaledPESModel nomenclature was confusing, as in fact the class (as described in #8) is actually implementing automatically unit-normally distributing energies to improve NN learning performance.

This PR:

• Renames the class UnScaledPESModel to AutoScaledPESModel
• Renames all references to the class across graph-pes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.99%. Comparing base (a89a2c2) to head (2d9a6ca).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #9      +/-   ##
==========================================
- Coverage   88.00%   87.99%   -0.02%     
==========================================
  Files          35       35              
  Lines        1968     1966       -2     
==========================================
- Hits         1732     1730       -2     
  Misses        236      236              

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[jla-gardner]

Thanks for the improvement - LGTM 👍