Core model and operator improvements, overhaul of pagination params

[munrojm]

This PR includes:

• Identify and include group info in header for CloudFlare rate limit settings
• List input supported for formula, working ion
• Ensure proper units in all document model descriptions -- Done in docs
• Endpoint information pointed to in summary fields -- Done in docs
• Rename limit and skip params

[codecov-commenter]

Codecov Report

Merging #368 (58a9829) into main (cfa03ca) will decrease coverage by 0.08%.
The diff coverage is 91.61%.

@@            Coverage Diff             @@
##             main     #368      +/-   ##
==========================================
- Coverage   92.27%   92.19%   -0.09%     
==========================================
  Files          85       85              
  Lines        4546     4574      +28     
==========================================
+ Hits         4195     4217      +22     
- Misses        351      357       +6     

Impacted Files	Coverage Δ
...api/emmet/api/routes/elasticity/query_operators.py	100.00% <ø> (ø)
emmet-core/emmet/core/base.py	100.00% <ø> (ø)
emmet-core/emmet/core/symmetry.py	93.75% <ø> (ø)
emmet-core/emmet/core/thermo.py	94.64% <ø> (ø)
emmet-core/emmet/core/xas.py	33.64% <36.36%> (ø)
...api/emmet/api/routes/electrodes/query_operators.py	98.33% <75.00%> (-1.67%)	⬇️
...-api/emmet/api/routes/molecules/query_operators.py	97.36% <80.00%> (-2.64%)	⬇️
emmet-api/emmet/api/routes/materials/utils.py	93.54% <88.88%> (-6.46%)	⬇️
emmet-api/emmet/api/routes/electrodes/utils.py	100.00% <100.00%> (ø)
...-api/emmet/api/routes/materials/query_operators.py	92.43% <100.00%> (ø)
... and 15 more

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