This PR buckets up three changes:
- In the GraphQL schema for config types we rename name to givenName,
make it non-nullable, and move it to the only two subtypes that have
given names, enums and "regular" types.
- Flow Scalar Union down to GraphQL and render them in the config
editor. Typeahead still does not work
- Makes the input hydration config just a dictionary with "value",
"json", and "pickle" keys rather than a scalar union, which in the
case of Any was an ambiguous parse.