FR: mullvArd Add-on, remove and add devices

### What are you trying to do?

I am successfully using mullvArd VPN add-on as an endpoint. I am not clear about usage. If I have 10 devices on my tailnet, I may want to rotate them as Mallard devices which is limited to five concurrent devices. The best solution for me would be to have a bash script executed within my tailnet. I know the tailnet API allows removing devices from my tailnet, will it automatically be removed from the mullvArd Add-on? Actually I don't want to remove it from my tailnet, just from mullvArd VPN. Then add another device and this requires editing the ACL in node attr "mullvard". What I want is that removing attr "mullvard" in ACL removes device from mullvard VPN add-on. Can I replace devices in add-ons willy nilly?

### How should we solve this?

Can rotation of devices in mullvard VPN add-on be scripted?

### What is the impact of not solving this?

I will be editing the ACL often and manually removing and adding devices to mullvard VPN add-on.

### Anything else?

_No response_