Prior to this commit, the `GraphQLAutoConfiguration` would only consider
the case where the GraphQL schema is read as an SDL from a configured
location.
GraphQL also supports the programmatic creation of the schema and this
case needs to be supported by the auto-configuration.
This commit updates the auto-configuration to disable the schema
creation from the SDL if a `GraphQL.Builder` bean is already contributed
by the application.
Fixes gh-4
95bfe2e318