python: move AltField class to flux.util

Problem: The AltField class is only present in flux-resource.py,
but this class could be useful in other commands.

Move it to flux.util.

Author: grondo

src/bindings/python/flux/util.py

@@ -535,6 +535,24 @@ def format_field(self, value, spec):
         return retval
 
 
+class AltField:
+    """
+    Convenient wrapper for fields that have an ascii and non-ascii
+    representation. Allows the ascii representation to be selected with
+    {field.ascii}.
+    """
+
+    def __init__(self, default, ascii):
+        self.default = default
+        self.ascii = ascii
+
+    def __str__(self):
+        return self.default
+
+    def __format__(self, fmt):
+        return str(self).__format__(fmt)
+
+
 class OutputFormat:
     """
     Store a parsed version of the program's output format,

src/cmd/flux-resource.py

@@ -27,7 +27,7 @@
     resource_status,
 )
 from flux.rpc import RPC
-from flux.util import Deduplicator, FilterActionSetUpdate, UtilConfig
+from flux.util import AltField, Deduplicator, FilterActionSetUpdate, UtilConfig
 
 
 class FluxResourceConfig(UtilConfig):
@@ -203,24 +203,6 @@ def ranks_by_queue(resource_set, config, queues):
     return ranks
 
 
-class AltField:
-    """
-    Convenient wrapper for fields that have an ascii and non-ascii
-    representation. Allows the ascii representation to be selected with
-    {field.ascii}.
-    """
-
-    def __init__(self, default, ascii):
-        self.default = default
-        self.ascii = ascii
-
-    def __str__(self):
-        return self.default
-
-    def __format__(self, fmt):
-        return str(self).__format__(fmt)
-
-
 class ResourceStatusLine:
     """Information specific to a given flux resource status line"""