Make parsed tree more consistent

[aew]

• Modify grammar to simplify parser with ~30% fewer "special" functions and renamings
• Move to a consistent parse tree tracking the type of the node. Although more human readable and easier to interact with for lookups, using maps of key-value pairs for the parsed tree that comes out of instaparse's transform function for things like type-fields, variables, and arguments actually makes it harder to do validation (e.g., guard against duplicate keys) and is less consistent to walk the tree (things like zippers tracking the path into the tree may be useful for clojure.spec global naming, and could simplify type lookup and validation). Use a vector of maps instead.
  • Statements
  • Before: https://gist.github.com/aew/9a8508da64c03a8f26157de27ead9534
  • After: https://gist.github.com/aew/1bfa657743caa025e28d4fe83516c81d
  • Schemas
  • Before: https://gist.github.com/aew/d7ebe142283d37585761fdd859445f11
  • After: https://gist.github.com/aew/362da62a1cb949436a62f865118f83c6
• Fix root cause of the enum value ambiguity with boolean values. The spec states: EnumValue can be a Name but not true or false or null
• Consolidate parser tests (including CATS cases and others) in a single test namespace that can react to changes in the parser namespace (for things like prism)
• Fix :ListType parsing
• Use :argument-name and :field-name to remain unambiguous. Arguments can have both a :variable-name and an :argument-name and these were colliding when they were both called :name
• Simplify :selection-set parsed representation by removing the :selection and :field wrapping keys
  • Before: https://gist.github.com/aew/9a8508da64c03a8f26157de27ead9534#file-gistfile1-txt-L7
  • After: https://gist.github.com/aew/1bfa657743caa025e28d4fe83516c81d#file-gistfile1-txt-L10
• Simplify enum values in arguments by removing the :enum-value wrapper
  • Before: https://gist.github.com/aew/9a8508da64c03a8f26157de27ead9534#file-gistfile1-txt-L521
  • After: https://gist.github.com/aew/1bfa657743caa025e28d4fe83516c81d#file-gistfile1-txt-L489

[aew]

This is ok to merge from my side at this point, as introspection is working (with a new test).

[tendant]

This is great. Thanks a lot!