nixos/tor: add HiddenServiceVersion option

[jonasnick]

Motivation for this change

Allows to easily use v3 Hidden Services which "features many improvements over the legacy system". Due to the torrc syntax that seems difficult to do without adding a hidden service version option to the module.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[oxij]

type = types.addCheck (types.nullOr types.int) (x: x == 2 || x == 3);

I think it should be

type = types.nullOr (types.addCheck types.int (x: x == 2 || x == 3));

(Btw, grepping shows `nixos/modules/services/misc/rippled.nix` does a similar wrong thing. I fixed that one myself and added the patch to the queue.) Also, after reading #50849 (review) I'm now also a bit torn on whenever the default should be left to tor via `null`s, via `isDefined` or at all. But I'd say it's fine as it is.

[jonasnick]

Good catch. I fixed that. Actually I found the construction in rippled.nix and then didn't think about it.

[infinisil]

Another type revision:

types.nullOr (types.enum [ 2 3 ])

[jonasnick]

Makes sense. Done.

[oxij]

LGTM.