Perform the Euclidean distance between the current position of a node and its destination (Point of Interest).
[D]=MobilityDistanceNPoi(nx,ny,dx,dy)
node x-coordinate (current position).
node y-coordinate (current position).
node PoI x-coordinate.
node PoI y-coordinate.
Euclidean distance.
MobilityDistanceNPoi performs the Euclidean distance between the current position of a node (nx,ny) and its destination (dx,dy) (Point of Interest).