Put its contents in it and then use them from there instead of importing them
all over the rest of the code.

Remove the VirtualBox GUI, see
https://search.nixos.org/options?channel=21.05&show=virtualisation.virtualbox.host.headless&from=0&size=50&sort=relevance&query=virtualbox

... if you are reading this not in the repo, but from the web page, you might
not know where to go to make all those nice commands work.

... clean up 

Less (SLOC) is more

... so Grafana shows us names instead of VPN IP addresses.

Avoiding catastrophy: It's all about minimizing cognitive overhead.

- Add node exporter to nodes
- Make the old nixpkgs 19.09 node exporter work (amend config)
- Fix a typo (??) and exclude monitoringvpn in network traffic graphs to prevent double counting

... leave some coding fun for later!