Manage all build nodes under one network

[grahamc]

Right now there are a few groups of managed build nodes. This makes it difficult to ensure they're all running consistent versions of Nix and NixOS, and are participating in the monitoring.

• [ ] Import the x86 Linux machines in to the network:

  • [x] packet-epyc-1
  • [x] packet-t2-4
  • [ ] t2a
  • [ ] t4a
  • [ ] t4b

• [x] Import the macOS-on-Linux machines in to the network:

  • [x] mac2-host
  • [x] mac3-host
  • [x] mac6-host
  • [x] mac7-host

• [x] Convert the remaining macOS-on-Darwin machines to be macOS-on-Linux and import in to the network:

  • [x] mac1
  • [x] mac4
  • [x] mac5
  • [x] mac8
  • [x] mac9

• [ ] Import the aarch64-linux machines in to the network:

  • [ ] add an aarch64 remote builder to the deploy host
  • [ ] packet-t2a-1
  • [ ] packet-t2a-2

[grahamc]

cc @vcunat I'll need help / configs from you for t2a/t4a/t4b

[vcunat]

Yes, I had it in my TODO after our talking about it. I'll need to figure out how to integrate my custom changes – I expect to PR a suggestion.