Add Pop!_OS 24.04

[rgl]

Describe the solution you'd like
Add Pop!_OS 24.04 to https://github.com/netbootxyz/netboot.xyz/blob/development/roles/netbootxyz/templates/menu/live-popos.ipxe.j2

[Kwakx]

I was just about to use netboot for the first time, only to find out that this version is not available. +1