This profile does the following:
- it enables the elastic apt repo
- it also enables the network during installation
- finally, it makes sure to exclude the very big package
exploitdb-papers, otherwise the iso is too big (~ 6 GB)
I'm a bit surprised that we need to enable the network via a preseed
file. I thought that it would be enough to just make sure that the
installer-purple variant does NOT include the offline profile, but in
practice no, it's not enough.