UI updates to include "overlay kind"

internal/app/wwctl/overlay/build/root.go

@@ -4,19 +4,17 @@ import "github.com/spf13/cobra"
 
 var (
 	baseCmd = &cobra.Command{
-		Use:   "build [flags] <overlay name>",
+		Use:   "build [flags] <overlay kind> <overlay name>",
 		Short: "(Re)build an overlay",
 		Long:  "This command will build a system or runtime overlay.",
 		RunE:  CobraRunE,
+		Args:  cobra.ExactArgs(2),
 	}
-	SystemOverlay bool
-	BuildAll      bool
+	BuildAll bool
 )
 
 func init() {
-	baseCmd.PersistentFlags().BoolVarP(&SystemOverlay, "system", "s", false, "Show System Overlays as well")
 	baseCmd.PersistentFlags().BoolVarP(&BuildAll, "all", "a", false, "Build all overlays (runtime and system)")
-
 }
 
 // GetRootCommand returns the root cobra.Command for the application.