This commit adds the required infrastructure to auto-configure a
`GraphQlTester` or `WebGraphQlTester` in Spring Boot tests.
Specific annotations like `AutoConfigureGraphQlTester` and
`AutoConfigureWebGraphQlTester` will contribute pre-configured beans for
testing a GraphQL with the tester.
This also ships a `ContextCustomize` for contributing a `GraphQlTester`
in the case of a full `@SpringBootTest` integration test against a live
server.
See gh-29140
c0707e4f5b