GraphQL+- -> Spec Compliant GraphQL

This has been requested before, but since we’re aiming for spec compliant GraphQL, I thought I’d put this here.

Lists in Dgraph behave like an unordered set, which makes perfect sense from a graph point of view, but they do not suit all types of data. The GraphQL spec says that “lists are ordered sequences of values”, and I think we should aim for that.

In DQL, if we want to use unordered lists for performance benefits, perhaps we could create a directive to guarantee order?