This reduces the confusion with the nixos/modules/deployment.nix module,
and should make it clearer that it can contain any configuration that
applies to all hosts on the grid.

Using AWS is what causes it so using AWS can be what fixes it, too.

... This breaks the tie, thx to https://github.com/DBCDK/morph/issues/146

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

Also change the `domain` parameter for Grafana to always
use that beautiful name - besides display it's cosmetic anyway
IIANM so I'll not parametrize it for now.

More flexibility and less dots in config files.
Implements #65.

Discern make-issuer.nix from issuer.nix better.