This adds new outpus like `format` and `formatNoDeps` which
are compatible with `nix run` so you can do something like
nix run .#nixosConfigurations.myhostname.config.system.build.formatNoDeps
as originally intended in #78, or add disko to your configuration like
environment.systemPackages = [
config.system.build.format
config.system.build.mount
config.system.build.destroyFormatMount
];
as mentioned in #454.
Fixes part of #454
Supersedes #78
It also deprecates mode `disko` in favor of the clearer
`destroy,format,mount` and adds `format,mount` to allow easier in-place
updates.
Apply standard formatting and some statix conventions using;
```sh
nixpkgs-fmt **.nix && statix fix .
```
With the intent of making contribution a bit easier and reducing mental
load in hand formatting (in the same vein as [black]).
[black]: https://github.com/psf/black#the-uncompromising-code-formatter
