feat(models): Updating PHES to reflect latest version of PSY.

[pesap]

This PR adds the correct model field for storage_capacity for HydroPumpedStorage and also changes the way we create named tuples. It turns out that if we create classes, the serialization is easier without to much compromise. Pydantic knows how to create the dict and deserialize it allowing us to deprecate the custom serialization.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.16%. Comparing base (4624441) to head (a176225).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #144      +/-   ##
==========================================
+ Coverage   82.11%   82.16%   +0.04%     
==========================================
  Files          41       42       +1     
  Lines        4306     4318      +12     
==========================================
+ Hits         3536     3548      +12     
  Misses        770      770              

Files with missing lines	Coverage Δ
src/r2x/exporter/plexos.py	90.00% <100.00%> (+0.02%)	⬆️
src/r2x/models/__init__.py	100.00% <100.00%> (ø)
src/r2x/models/branch.py	92.77% <100.00%> (+0.08%)	⬆️
src/r2x/models/generators.py	99.06% <100.00%> (+<0.01%)	⬆️
src/r2x/models/named_tuples.py	100.00% <100.00%> (ø)
src/r2x/models/services.py	93.75% <100.00%> (-0.54%)	⬇️
src/r2x/parser/plexos.py	73.35% <100.00%> (-0.14%)	⬇️
src/r2x/parser/reeds.py	90.88% <100.00%> (-0.03%)	⬇️