Refactor State to use std::any and a more rigorous update pattern

[jmikeowen]

Summary

• This PR is a feature improving the way we handle checking in and update state fields in the State objects.
• It does the following:
  • We have converted the State objects to use std::any rather than boost::any to hold all state fields.
  • The update, equivalence, clone, and zeroing operations now rely on a generic visitor pattern to ensure all data types are handled in those operations.
  • We have eliminated the cascade of try/catch the old objects used for this, which would also silently pass for fields that were not handled.
  • We renamed the getAny and enrollAny methods of StateBase to all be simply overloaded versions of get and enroll. These older names were to simplify Python bindings using disambiguated names, but this simpler overloading of uniform names was always the intended usage. Most of the files touched in this change are due to this interface simplification.

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ToDo :

• Annotate RELEASE_NOTES.md with notable changes.
• Create LLNLSpheral PR pointing at this branch. (PR#)
• LLNLSpheral PR has passed all tests.