Review ResourceChangeListeners

[joerghoh]

I came across the behavior that any ResourceChangeListener is notified when a servlet is unregistered/registered (more precise: when their corresponding ResourceProvider is unregisted/registered) if the property resource.change.types is not defined. This happens quite often during deployments.
Depending on the implementation of the ResourceChangeListeners this can have a huge performance impact on deployments.

This issue is to validate all implementations of this service interface and check if they need to handle such (un-) registrations or if they are searching for simple resource changes in the repository.

[joerghoh]

If enabled JcrNodeChangeEventHandler (part of the httpcache) creates a new (Sling) job on stop/start of a Servlet. This is not necessary.

[joerghoh]

The ConfigurationUpdateListener of the Automatic Package Replicator feature refreshes its cache also on every start/stop of a servlet, which isn't necessary.

[joerghoh]

SystemNotificationsImpl has this property defined and does not need any change.

[joerghoh]

fix in #2268

[joerghoh]

commit merged, thanks!