Add repository beans

[hwellmann]

The extension should automatically add a bean of type Repository<Foo> for each aggregate Foo.

This would enable users to simply write

@ApplicationScoped
public class BankAccountCommandHandler {

    @Inject
    private Repository<BankAccount> repository;

    @Inject
    private EventBus eventBus;
}

saving a producer method and an explicit constructor for BankAccountCommandHandler.