Feature request: Authentication support for integration test using GraphQLSpec trait

Using Spring Security together with GORM GraphQL we want to be able to add authentication headers in our integration tests to validate our app security, data integrity and tenancy that has been setup with GraphQL interceptors and Spring Security configuration.

This can be done by attaching GET parameter /graphql?access_token=XXX or allowing developer to add HTTP headers to RxHttpClient.

Start by locating the GraphQLSpec trait and RxHttpClient integration-test support mentioned in the issue, then reproduce a test using Spring Security and GraphQL interceptors. Done means an integration test can provide authentication headers or an access token and validate the secured GraphQL behavior.

Written by the indexing model from the issue text.