[Engine - Pathfinder] Encapsulate node from BlueRaja

[persn]

The BlueRajaWrapper class needs a node of the type FastPriorityQueueNode which is inherited from the OptimizedPriorityQueue framework. We should encapsulate this class so that every project making use of our BlueRajaWrapper also doesn't have to reference the OptimizedPriorityQueue framework.