GraphQL: make sure that interface implementations all accept the same arguments for each field

[lutter]

This came up in the review of PR #1341

[azf20]

@lutter @dotansimha do you know if this issues still applies?

[lutter]

Yes, I don't think anything has changed there. This would be a validation that should go into graph-cli and into the validation of the GraphQL schema when a subgraph is deployed in graph-node