MODE-2323 Removed the proxy layer and delta write functionality in Schematic

ModeShape's is no longer using Infinispan in ways where these pieces of functionality are useful.
Removing them should simplify the logic to represent more of what we're actually doing. See MODE-2323 for details.
I don't think we require `PESSIMISTIC`: single writer multiple reader scenarios can be (are) common in which case `PESSIMISTIC` should not be required. Similarly, the case when clients know they only update concurrently disjoint parts of a hierarchy.

From a code perspective, I don't know really what happens on `cache.lock` if the configuration is not `PESSIMISTIC`. If it's a no-op or there's 0 overhead, then I'm fine always doing this. I think having the `edit` method that you suggested (with a boolean flag) would be fine.