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.
The problem is in the [LocalDocumentStore.DistributedOperation](https://github.com/ModeShape/modeshape/pull/1280/files#diff-4af11516afd868140f021cf81807bcd9R382) class, which operates only upon the `Cache` (without the `Schematic` instance). I'lll see if I can create a `Schematic` instance there, in which case I think I can clean this up.