Added some Cobra framework for new command groups as I'm thinking through the interface.

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

@@ -0,0 +1,32 @@
+package show
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+)
+
+var (
+	showCmd = &cobra.Command{
+		Use:                "show",
+		Short:              "Show Warewulf Overlay objects",
+		Long:               "Warewulf show overlay objects",
+		RunE:				CobraRunE,
+	}
+
+)
+
+func init() {
+
+}
+
+// GetRootCommand returns the root cobra.Command for the application.
+func GetCommand() *cobra.Command {
+	return showCmd
+}
+
+
+func CobraRunE(cmd *cobra.Command, args []string) error {
+
+	fmt.Printf("Show: Hello World\n")
+	return nil
+}