Add loader for graphql files

[patrick91]

This is going to land in the next version of create react app, would be nice to have it here as well :)

https://github.com/facebook/create-react-app/pull/3909/files

[Slessi]

It seems they've reverted the change with facebook/create-react-app#5076

In favor of using https://github.com/evenchange4/graphql.macro