Create service for handling JCR changes in CM to Experience Pages

Create a service that supports CRUD operations for Experience Pages.

It will use an impersonated session to interact with the repository.

Branching support for unpublished variant is covered in https://issues.onehippo.com/browse/ENT-1772

Most likely it has to use the workflow manager similar to document workflow, it must result in audit logging also see CMS-13160 and CMS-13199. in the CM, only when explicitly clicking a button to create a version of the Experience Page, a version history item should be created. Thus not on every change in the layout (note that every commitEditableInstance for the content we do want for experience pages a new version)

ADDITION Note that it took me quite a long time while working on CMS-13159 to find out that when writing directly to the unpublished variant we MUST NOT forget to update

hippostdpubwf:lastModificationDate

Otherwise we will get problems with branches, since restoring a different version from version history only creates a new version for the unpublished variant IF it has an updated hippostdpubwf:lastModificationDate time, see

org.onehippo.repository.documentworkflow.DocumentHandle.isCurrentUnpublishedVersioned()