select/cray: overload meaning of NodeAddr/NodeHostname in multiple-fronted mode

This implements Moe's suggestion for NodeAddr/NodeHostname semantics,

   NodeName     "nid#####"    (this is what SLURM will refer to the node as)
   NodeHostName "c0-0c0s0n1"  (Cray's component ID, visible only with scontrol
		                                and sview's node display)
   NodeAddr     "###"         (hexadecimal X, Y and Z coordinates, visible only
		                                with scontrol and sview's node display)

For example,
palu> scontrol show node nid00189
NodeName=nid00189 Arch=XE CoresPerSocket=6
   CPUAlloc=0 CPUErr=0 CPUTot=24 Features=(null)
   Gres=(null)
   NodeAddr=01E NodeHostName=c1-0c0s1n1
   RealMemory=32000 Sockets=4
   ...

Please note:
~~~~~~~~~~~~
on XE systems each two nodes (0/1 and 2/3) on a node share the same network
interface and hence are located at identical Y coordinates in the torus. To
make tools such as smap work with these coordinates, we use "virtual" Y
coordinates, computed as

  y_coord = 4 * cage + cpu;

This scheme mirrors the one currently used to derive node coordinates on a
SeaStar/XT system.

09_Cray-hostlist.diff