librewolf: init module

[onny]

Description

This PR is related to the issue #2803 .
It adds a module for the program LibreWolf, a security and privacy focused fork of Firefox.
In the current state it only adds the overrides settings to configure some LibreWolf settings as described here. This is the only option I need.
As far as I can tell this is Librewolf specific and could not be compared or covered with the Firefox module.

Example usage:

programs.librewolf = {
  enable = true;
  # Enable WebGL, cookies and history
  overrides = {
    "webgl.disabled" = false;
    "privacy.resistFingerprinting" = false;
    "privacy.clearOnShutdown.history" = false;
    "privacy.clearOnShutdown.cookies" = false;
    "network.cookie.lifetimePolicy" = 0;
  };
};

This configures Librewolf to enable WebGL, remember cookies and history by disabling privacy and security defaults.

Checklist

• Change is backwards compatible.

• Code formatted with ./format.

• Code tested through nix-shell --pure tests -A run.all.

• Test cases updated/added. See example.

• Commit messages are formatted like

  {component}: {description}
  
  {long description}
  

  See CONTRIBUTING for more information and recent commit messages for examples.

• If this PR adds a new module

  • Added myself as module maintainer. See example.

  • Added myself and the module files to .github/CODEOWNERS.

[onny]

@sumnerevans

[onny]

@kubukoz

[onny]

@somasis :)

[rycee]

Thanks! Added a few comments.

[onny]

Thank you @rycee, fixed the issues :)

[sumnerevans]

Sorry, just noticed a couple other minor things.

[onny]

Thank you @sumnerevans for the feedback :) Fixed it!

[rycee]

Thanks! Merged to master now. Note, I made the module Linux only since the librewolf package in Nixpkgs doesn't seem to support Darwin.