The GraphQL Spring Boot starters aren't actually necessary.
The typical GraphQL usage is really tied to the type of web application
you're building: Spring MVC or WebFlux.
Adding the `spring-graphql-web` dependency to the classpath is a signal
strong enough that we can configure additional endpoints into the web
application.
Closes gh-17
This commit refactors the Gradle build with the following:
* use of the dependency management plugin
* import the Spring Boot BOM for dependency management
* add support for publishing artifacts
