Hibernate integration should set AvailableSettings.CLASSLOADERS instead of deprecated AvailableSettings.APP_CLASSLOADER

Since Hibernate ORM 5.0, AvailableSettings.CLASSLOADERS has been available to to define a

of the

instances Hibernate should use for class-loading and resource-lookups.

I think that we could switch to using that instead of the:

properties.put(AvailableSettings.APP_CLASSLOADER, pu.getClassLoader());

that we do now.

Also see the code to be changed https://github.com/wildfly/wildfly/blob/master/jpa/hibernate5_3/src/main/java/org/jboss/as/jpa/hibernate5/HibernatePersistenceProviderAdaptor.java#L76, since APP_CLASSLOADER is deprecated and will be dropped at some point, so we should start preparing for that.