hardware/u2f: remove module

udev gained native support to handle FIDO security tokens, so we don't
need a module which only added the now obsolete udev rules.

Fixes: https://github.com/NixOS/nixpkgs/issues/76482

nixos/modules/services/hardware/u2f.nix

@@ -1,23 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-let
-  cfg = config.hardware.u2f;
-in {
-  options = {
-    hardware.u2f = {
-      enable = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Enable U2F hardware support.
-        '';
-      };
-    };
-  };
-
-  config = mkIf cfg.enable {
-    services.udev.packages = [ pkgs.libu2f-host ];
-  };
-}
-