Support hot plugging network interfaces

name: Feature request
about: Suggest an idea for this project

I'm migrating to kea from the previous ISC DHCP4 server and I noticed a difference in behavior. Kea refuses to start if an interface declared in interfaces-config is not present when Kea starts.

I want to be able to declare subnets & definitions for a USB adapter that I sometimes hotplug to the gateway. Without support from Kea, I'd need to keep two different configs and reload Kea at appropriate times. I assume it's also going to fail when a network interface it's listening on disappears.