Remove command channel from mailman headset/remove mailman headset from qm locker

[Emimiyu]

I find it a bit weird that QM now has easier access to command radio as a non command. Command radio channel should be more secure and, lately, I have seen many QM quickly switch to mailman headset.

I am suggesting for either command radio channel to be removed from mailman headset or removal of the mailman headset from cargo lockers, so it is exclusive for mail courrier only (they can still have command channel)