Support for OperationName

[la-we]

I'd like to implement support for operation names as of https://graphql.org/learn/queries/#operation-name

My idea would be to implement support for this as an additional attribute that can be attached to the POCO of the operation itself, i.e.

[GraphQLOperationName("OpName")
class MyMutation {
[GraphQLArgument("test")]
public string ActualMutation {get; set;}
}