MODE-2088 Eliminated the ring buffer's ability to submit entries in the same thread, which simplifies the consumers and makes them not need to be concurrent. Also changed the WorkspaceCache to register its own listeners that are better optimized for what they do. Kept the ability for the RepositoryChangeBus to have in-thread listeners (notified in the caller's thread), but these listeners only receive events via this route. Changed the JcrRepository to register various listeners directly on the bus rather than via the RepositoryCache (which was a listener and just delegated the register and unregister methods to the change bus). At this point, all tests pass successfully (multiple build passes).