refactor: export more things from graphqlbackend to support separating into multiple packages

Created by: sqs

The graphqlbackend is a huge package right now. We are trying to extract more things from it (such as ./enterprise/cmd/frontend/internal/{licensing,registry,dotcom/{billing,productsubscription}}, all of which contribute GraphQL resolvers but are in separate, well encapsulated packages). The extracted packages do need to access certain definitions in the graphqlbackend package, so it is necessary to export some more things from it.

This commit is entirely automated codemods.