When leaving a specific document's editor, persist the transient jcr session changes

In CMS-10514, it was made sure that when switching perspective, the session in memory changes would be saved. However, it should be more generic.

What currently can happen is that an editor changes document A and changes document B. Meanwhile, someone changes a field of document B in the console (or some background process, for example an importer). Then document B cannot be saved by the editor anymore since it is already modified (conflict). But now the editor also cannot save Document A anymore.

To make the impact smaller, a more generic solution for CMS-10514 will be to always save a session when the 'editing context' of a document is left. If this is done, the changes in CMS-10514 should be reverted.

When the session save as a result of leaving the 'editing context' results in a jcr error (for example already modified), the CMS should popup a error message that the transient changes will be lost due to other modifications : The backend must do a

session.refresh(false) 

in that case to flush the changes that have issues