Added a FlakeCoordinationManager interface for general pellets as well as a specialization for reducer pellets.
This coordination manager may be used for 'distributed' coordination among the different instances of the flakes for a given pellet.

The reducer coordination manager, assigns itself a random token on the ring and then coordinates with other flake instances to find the 'K' counter clockwise neighbors (wrapping around if required) on the ring. These 'K' neighbors will be used for peer-backup and peer-checkpointing.