Patch Jackrabbit to provide a dedicated system session in the SharedItemStateManager

For REPO-2215 we need a system session in the SharedItemStateManager to support hierarchical domain constraints on not (yet) existing paths.
This will be implemented in the HippoSharedItemStateManager (see REPO-2215), but needs to be initialized (seeded) with a dedicated system session from within Jackrabbit initialization, hence the needed patch.