intended to swap out nixos-anywhere for terraform-nixos, over:
- don't need nixos-anywhere to install nixos; we preload nixos to VMs
- [awkward non-flake
usage](https://nix-community.github.io/nixos-anywhere/howtos/use-without-flakes.html#3-set-nixos-version-to-use)
- seemed not to pick up on config changes, as observed by test VMs
losing their panel keys after TF sync
however, it seems that terraform-nixos has its own flaws:
- its output using a random id, i.e. forcing to push even on no changes
- so far did not get ssh authentication to work