Deleting classes that are currently not in use

Simplifying the code by deleting the classes that aren’t in use as part
of the refactor.  Backup code can be added into the refactored design
once ready.  Currently, this code is not in use and is not functional.
If/when we do eventually want to do this, we should probably just use the Mesos state abstraction, and maybe add S3/GCS as storage backends. The state abstraction already has a store/fetch/expunge/list API.