feat(label): address labels by name and add import and clone

label edit bug and label delete kind/feature failed with "invalid resource
number", and label create took its name as --name and required
--color. Like gh, label create takes the name as an argument and picks
a random color without -c; label edit and delete take names or IDs
(delete several at once, after a confirmation that names them), and
-c/-d/-n/-f are the gh short flags. Without a name on a terminal, label
create asks for the name, color and description.

label list shows ID NAME COLOR DESCRIPTION FLAGS with a colored swatch
and exclusive and archived labels flagged. Mutations report ✓ lines.
label import reads a label file or stdin (label create --file still
works), label clone copies another repository's labels, skipping those
that exist unless --force, and label export writes to stdout by default
or to -O/--output.

Signed-off-by: bircni <bircni@icloud.com>

internal/app/app_test.go

@@ -265,7 +265,7 @@ func TestCommandHelpShowsRelevantFlagsOnly(t *testing.T) {
 	}
 	out.Reset()
 	require.NoError(t, Execute(context.Background(), deps, []string{"label", "list", "--help"}))
-	require.Contains(t, out.String(), "\nFLAGS\n  -L, --limit int    Maximum number of results (1..1000) (default 30)\n      --org string ")
+	require.Contains(t, out.String(), "\nFLAGS\n  -L, --limit int          Maximum number of results (1..1000) (default 30)\n      --org organization ")
 	for _, args := range [][]string{{"version", "--help"}, {"alias", "list", "--help"}, {"auth", "status", "--help"}} {
 		out.Reset()
 		require.NoError(t, Execute(context.Background(), deps, args))
@@ -424,11 +424,6 @@ const (
 	issue attachment list
 	issue attachment upload
 	issue attachment view
-	label create
-	label delete
-	label edit
-	label export
-	label list
 	milestone close
 	milestone create
 	milestone delete
@@ -454,7 +449,6 @@ const (
 `
 	longsToWrite = `
 	issue attachment
-	label
 	milestone
 	milestone issue
 	pr attachment