[WIP] Handle NAGLCharges

[j-wags]

See openforcefield/openff-interchange#1206 for corresponding changes in Interchange

• Tag issue being addressed
• Add tests
• Update docstrings/documentation, if applicable
• Lint codebase
• Update changelog

[codecov]

Codecov Report

Attention: Patch coverage is 80.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 82.59%. Comparing base (f4fff54) to head (10db658).

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[mattwthompson]

For better or worse, Interchange does not use this and I don't think anything else does

[mattwthompson]

While there is always the potential for surprises, I like this implementation and believe it will be better than how NAGL-based charges are currently applied, which relies on isomorphism checks and has the potential to be very slow for large molecules (see #2072 for a fun example)