Allow enum cases to be inferred if type conforms to `CaseIterable` about graphiti HOT 2 CLOSED

Earlier versions of the library allowed things like this. For example, it was possible to simply set the Swift type for a GraphQL type and we would use reflection to expose all of the properties as GraphQL fields automatically. I eventually arrived at the conclusion that that wasn't a good idea so now we require everything to be exposed explicitly. The main goal is to have the schema be like a mirror to a GraphQL schema file. No hidden surprises. You read the schema, you know the truth.

from graphiti.

Another reason to require the schema to be explicit is that it might encourage developers to add descriptions to the API. With reflection or CaseIterable, for example, we wouldn't have a proper way to add descriptions.

from graphiti.