While during a print prevent Host Control Shutdown or Reboot

[KiwiChrist]

Please add feature to prevent accidentally pressing the shutdown or reboot during a print under Host Control, a bit like the {power] "locked_while_printing: True".

While printing "Host Control" access in the rh side drop down menu should be greyed out and not accessible. The print has to be canceled to be able to reboot or shutdown.

Thanks.