execute './.ww4/runExit` on exeit of container exec

internal/app/wwctl/container/exec/child/main.go

@@ -85,6 +85,16 @@ func CobraRunE(cmd *cobra.Command, args []string) error {
 		wwlog.Printf(wwlog.ERROR, "%s\n", err)
 		os.Exit(1)
 	}
+	_, err = os.Stat("./.ww4/runExit")
+	if os.IsNotExist(err) {
+		wwlog.Printf(wwlog.DEBUG, "no exit script")
+		return nil
+	}
+	err = syscall.Exec("./.ww4/runExit", []string{""}, os.Environ())
+	if err != nil {
+		wwlog.Printf(wwlog.ERROR, "%s\n", err)
+		os.Exit(1)
+	}
 
 	return nil
 }