nixos: tailscale: option to disable path warning

[colemickens]

Description of changes

fixed #194623 by adding an option services.tailscale.ignoreReversePathFilter to quiet a warning that is relevant to only some tailscale clients/users.

cc: @LunNova @danderson

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[colemickens]

Crap, I fixed this on the wrong branch. Thanks @LunNova

[colemickens]

I guess I was fixing it in the right place, cherry-picking it to my usual nixpkgs and just forgot to push. Should be good now.

[LunNova]

@ofborg eval

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/prs-already-reviewed/2617/637

[SuperSandro2000]

Do we have any other options to silence warnings?

[colemickens]

Not that I'm aware of. It would be nice if there were some way to force them to have unique identifiers and then allow the user to opt-"in" to ignoring it the same way they can opt-"in" to ignore unfree-restrictions and use unfree packages. But, I don't think that exists.

[SuperSandro2000]

I was thinking the same thats why I am not that keen about adding this.

[ncfavier]

Let me just mention that there are discussions upstream about fixing the underlying problem so that we eventually wouldn't need a warning.

[LunNova]

Fine with this not getting in if it's too hacky. Would a more thought out system for silencing warnings need an RFC?

To solve the warning being annoying locally I could just patch it out anyway.

[LunNova]

Existing RFC which discusses adding a way to disable warnings, RFC 0127:

https://github.com/NixOS/rfcs/pull/127/files#diff-e089f932103f6decfd159bd39420f43fd834106b788fa06956e771ffd0cda991R63

[LunNova]

Fixed by #201119