Allow disabling document field validation on JSF widgets

DocumentValidationService exposes an extension point to deactivate the validation on creation (CoreSession.createDocument), modification (CoreSession.saveDocument) and import (CoreSession.importDocuments).

But there is no way to do it for the JSF validator DocumentConstraintValidator: so the constraints are always enabled in JSF forms (create/edit)

You can now disable the document constraint validation in creation and modification forms.