This commit does not change the semantics, only the looks.

At least it's easy to turn on

This is used in constructing the Google OAuth2 login callback URL and has to
match what's configured in Google - also helps if it is actually the address
of the server.

The old version of nixpkgs let us get away with setting neither isNormalUser
nor isSystemUser but setting all of the things a normal user would get
directly.  The new version of nixpkgs demands one of these flags be set.  So,
set it, and remove all of the redundant settings that it implies.

I hope I'm almost done with this branch.

Fewer lines almost always better.  Also, we don't want to spread
these out unless we have to.

Seems this is opt-out:
https://github.com/NixOS/nixpkgs/blob/9d1350d9d56411b685ff3de5839ed6728b1bf808/nixos/modules/services/monitoring/grafana.nix#L576-L582

Known issues:

  - Error rate tooltip computes over whole range (sum), should be per second or per minute or so
  - Duration buckets not great. Should also be per second probably.

They're only example but they scare me when they show up in grep results

They're only example but they scare me when they show up in grep results