Add Cuthill-McKee algorithm for node sort

[millerta]

From Rao, The basic algorithm is fairly simple (IIRC). Start with a node at an “extremity” (loose definition) numbered 1, collect its unvisited edge connected neighbors and label/number in order and stick them in the queue, pop the next node in the queue and repeat. This is the Cuthill-McKee algorithm. If you reverse this numbering at the end of the process, it is RCM.

[millerta]

Working on metis outside of LaGriT for sorting grids. If metis works, this will not be as high a priority.