DATAJPA-612 - Allow @EntityGraph on a method inherited from JpaRepository.

We now respect the @EntityGraph annotations on redeclared CRUD methods. CrudMethodMetadata now looks for @EntityGraph annotations, and - if present - the appropriate entity graph configuration is applied within SimpleJpaRepository.applyRepositoryMethodMetadata(…).

Previously we mistakenly treated the @EntityGraph annotation as a Query annotation which triggered a query resolution process that tried to find a named or create a derived query and failed. Removed @QueryAnnotation from @EntityGraph, since it should only be used to mark store specific @Query annotations.

Renamed Jpa21QueryCustomizer to Jpa21Utils. Moved Jpa21Utils to org.springframework.data.jpa.util to avoid potential dependency cycles.

Added EclipseLink and OpenJPA specific subclasses for the EntityGraphRepositoryMethodsIntegrationTests to make sure the tests are executed for EclipseLink and OpenJPA as well.

Original pull request: #109.