Consider removing apt-cacher-ng usage from our Jenkins build jobs
Our apt-cacher-ng would need some tweaks to be a bit more smart regarding building in Jenkins, but at the same time it does not make much sense to use an APT cache on the isobuilders while all the packages they are downloading are already hosted on lizard.
So we should probably just remove the apt cache configuration from our isobuilders. We need to test to see if it breaks something or improve the build time though.
A couple things were already attempted in this area, see https://git.tails.boum.org/puppet-tails/log/files/apt-cacher-ng/isobuilds.conf as a starting point.
- Blocked by #17075