Refactor blueprint to be per service

[gnawf]

Pending #403 and need to rebase onto master to get Artyom's blueprint changes.

Effectively this change uses the more correct way to collect services types that the validation has been doing i.e. uses getServiceTypes and getReachableTypes to collect all the types a service uses.

This improves the way we handle shared types as blueprints are now per service, which is actually a better view as we only execute the "query" on one service at a time anyway.

Stuff is not final and am happy to discuss this change.

Please make sure you consider the following:

• [ ] Add tests that use __typename in queries
• [ ] Does this change work with all nadel transformations (rename, type rename, hydration, etc)? Add tests for this.
• [ ] Is it worth using hints for this change in order to be able to enable a percentage rollout?
• [ ] Do we need to add integration tests for this change in the graphql gateway?
• [ ] Do we need a pollinator check for this?