Have an option to return multiple aliases for the same field #501

Currently we allow returning only as many fields as defined in the schema using Define.Object.

However GraphQL allows for querying additional output fields by aliasing existing ones.

query {
  People {
    name
    friends
    girlFriends: friends @filter(gender: Female)
  }
}

Notice how friends and girlFriends both refer to the same underlying friends field.

Currently this library does not provide for this functionality:
it does return both friends and girlFriends but both have identical content.