Consider removing ant01 and sib from our shared infrastructure

Since they were upgraded to Bullseye, ant01 and sib are broken, as in: they cannot run builds & tests due to networking/firewalling issues. I failed to quickly fix that and back then sysadmins suggested to me that the upcoming firewall rewrite would simplify things and hopefully make it easier to fix this problem.

It's now been 6 months, during which my dev workflow has been impacted negatively.

That's why, a couple weeks ago, I expressed the desire to move ant01 and sib out of our shared infrastructure, as the cheapest way to allow me to use them again.

Practically this means:

• They would not be managed by our Puppet master anymore.
• They would not be on our infra VPN anymore.
• Sysadmins would not have access to these machines anymore.

Initially @zen was all for it, but after I listed a bunch of pros & cons, he said he needed to think more about, so we put the decision on hold.

Meanwhile lots of progress was made on the firewall rewrite (#17950 (closed), that I suppose puppet-tails!100 (merged) will close). I understand it should be ready for deployment soon. I'm fine with waiting another few weeks for this to happen, and then we can see if it indeed allows fixing ant01 and sib easily. If it does not, we'll have to come back to this conversation. I would like this to be explicitly on our sysadmins' radar, hence this issue :)