nixos/automatic-timezoned: Fix boot delays and systemd unit ordering

[TLATER]

Since the service sets WantedBy=default.target, graphical.target ends up waiting for it to complete. Since geoclue.service, which this service depends on, in turn depends on network-online.target, this ends up making full boot wait for network availability.

This is obviously unintended; The unit should have always had an After=default.target.

Furthermore, the systemd docs recommend depending on specifically multi-user.target or graphical.target, rather than default.target. In practice, on a default NixOS system, using default.target delays starting this service until a graphical session starts - this is obviously not ideal, since it makes sense to update the timezone on a non-graphical system as well, so we fix that while we're at it.

Things done

• Built on platform:
  • [x] x86_64-linux
  • [ ] aarch64-linux
  • [ ] x86_64-darwin
  • [ ] aarch64-darwin
• Tested, as applicable:
  • [ ] NixOS tests in nixos/tests.
  • [ ] Package tests at passthru.tests.
  • [ ] Tests in lib/tests or pkgs/test for functions and "core" functionality.
• [x] Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• [ ] Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • [ ] Package update: when the change is major or breaking.
• NixOS Release Notes
  • [ ] Module addition: when adding a new NixOS module.
  • [ ] Module update: when the change is significant.
• [x] Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

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Add a :+1: reaction to pull requests you find important.

[TLATER]

@maxbrunet maintains the package, maybe you want to take a look?

[TLATER]

To save others the time (though I think it's quite obvious that the commit doesn't touch any packages):

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 470359 Commit: 718167630e3d15ac76f80b4f07f0a8febb2fb6eb

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x86_64-linux

:fast_forward: 2 packages blacklisted:

• nixos-install-tools
• tests.nixos-functions.nixos-test

:white_check_mark: 1 package built:

• nixpkgs-manual

[TLATER]

Thanks for the swift review :) As for upstreaming this, I think I've figured out enough contribution practices for repos for one weekend ;)