feat: refactor directives, add auth

[darahayes]

This PR does the following.

• Moves the complex logic from the hasRole SchemaDirectiveVisitor into a more simplified directiveResolvers map that follows a middleware style approach. This will ultimately make our directives compatible with graphql-modules
• Adds an @auth directive. This will support cases where the entire /graphql endpoint is not protected and users want to add auth to individual fields/mutations/queries
• tests for the auth directive
• moves tests all into one folder.

Next steps (in another PR) will be:

• Completely remove the SecurityService interface
• Expose directives and context provider directly
• examples and tooling to help users see the various use cases in action

[darahayes]

@wtrocki code coverage is being reported as a lower percentage because the originally the very large test files were being included in the percentage which drove it up. This number is the accurate number.

[wtrocki]

@darahayes I was just having a laugh :)