Support @PersistenceContext injection in CDI SE and CDI/Servlet environment

[hantsy]

Like Spring, add CDI decorations to provide injection for EntityManager and EntityMangerFactory for CDI SE and Servlet/CDI environment.

• CDI SE, the application is bootstrapped by a CDI container, even the embedded tomcat/jetty can be declared as CDI beans.
• Servlet/CDI, the application is war deployed into a standard servlet container that enabled CDI support via a servlet Listener.

I think there are some approaches already support this, such as Apache DeltaSpike and Quarkus, Helidon etc.

[arjantijms]

I'd go one step further and not just add some "decorations", but make the CDI way the primary way and deprecate the existing annotations. See https://github.com/eclipse-ee4j/jpa-api/issues/377

[gavinking]

See https://github.com/jakartaee/persistence/issues/377

Yeah, I think this and #377 are essentially the same issue. Or at least the solution would be the same.