DATAJPA-265 - Make it possible to configure auditing with Java Config.

Introduces the necessary infrastructure in form of JpaAuditingRegistrar to configure Auditing with JPA via Annotation config. The JPA Auditing feature can be enabled by annotating a configuration class with the EnableJpaAuditing annotation.

Note that this depends on DATACMNS-389 (spring-data-commons #53) to be applied.
DATAJPA-265 - Make it possible to configure auditing with Java Config.

Since we now trigger the dependency injection manually in the ctor of AuditingEntityListener we can remove the unnecessary bean dependsOn registrations from AuditingBeanFactoryPostProcessor.

Note that this depends on DATACMNS-389 (spring-data-commons #53) to be applied.
DATAJPA-265 - Make it possible to configure auditing with Java Config.

Applied suggested changes from code review.
Removed implicit bean instantiation in AuditingBeanFactoryPostProcessor since the declaration of an explicit dependsOn clause for the appropriate entityManagerFactory-factory beans triggers the bean initialisation of ABCA early enough. Since an entityManagerFactory defined as an @Bean AnnotationBeanDefinition doesn't have a beanClass set by spring we check whether the given bean definition is compatible to a EntityManagerFactory.

Note that this depends on DATACMNS-389 (spring-data-commons #53) to be applied.
DATAJPA-265 - Make it possible to configure auditing with Java Config.

Added audit configuration example to reference documentation.