Adds the following:
1. Serializes a workset to disk during setup.
2. Upon deserializing a RebootContext, delete the file from disk (We support rebooting once and only once)
3. Check if a workset exists with a RebootContext
1. If True, continuing processing
2. if False, mark the tasks & node as "Done" with appropriate errors via:
1. send WorkerEvent::Done events for each of the tasks in the work set
2. send StateUpdateEvent::Done for the node
