Add task storage `Warehouse`

[ethanholz]

This task covers the addition of ProtocolDAG object handling which in turn represents the entire task execution DAG in Warehouse. One thing that might be considered is that by default, task objects are optional since other implementations may not need to utilize this but we do so we can add exorcist. I am going to start work on this but I am open to any discussion on whether this should be optional or not.