flux-resource: use expandable formats in flux resource list

Problem: The fixed width of the queue field in `flux resource list`
causes confusion for users with overlapping queues because the queues
are joined into a comma separated list and truncation could cause
some queues to be completely left out of the field.

Now that the OutputFormat class supports "expandable" fields, use this
with the `queue` field in `flux resource list` so that no truncation
is guaranteed without using a large width by default.

Also apply the expandable field to ngpus to save some horizontal
space in the common case.

src/cmd/flux-resource.py

@@ -66,15 +66,15 @@ class FluxResourceConfig(UtilConfig):
         "default": {
             "description": "Default flux-resource list format string",
             "format": (
-                "{state:>10} ?:{queue:<10.10} ?:{propertiesx:<10.10+} {nnodes:>6} "
-                "{ncores:>8} ?:{ngpus:>8} {nodelist}"
+                "{state:>10} ?+:{queue:<5} ?:{propertiesx:<10.10+} {nnodes:>6} "
+                "+:{ncores:>6} ?+:{ngpus:>5} {nodelist}"
             ),
         },
         "rlist": {
             "description": "Format including resource list details",
             "format": (
-                "{state:>10} ?:{queue:<8.8} ?:{propertiesx:<10.10+} {nnodes:>6} "
-                "{ncores:>8} {ngpus:>8} {rlist}"
+                "{state:>10} ?+:{queue:<5} ?:{propertiesx:<10.10+} {nnodes:>6} "
+                "+:{ncores:>6} ?:+{ngpus:>5} {rlist}"
             ),
         },
     }