Persist Initial State Tracking Information
Persist Initial State Tracking Information

This commit ensures Replicator will persistently
write state tracking information to the Consul
Key/Value Store if no pre-existing state tracking
information exists.

Before this change, no distributed state tracking
information would be available until a scaling
action was initiated.

Closes #120.

elsevier-core-engineering/replicator,elsevier-core-engineering/replicator