nixos/dnsmasq: remove deprecated option "extraConfig"

- The `openlens` package got removed, suggested replacment `lens-desktop`

- The `services.dnsmasq.extraConfig` option has been removed, as it had been deprecated for over 2 years. This option has been replaced by `services.dnsmasq.settings`.

- The NixOS installation media no longer support the ReiserFS or JFS file systems by default.

- Minimal installer ISOs are no longer built on the small channel.

    listsAsDuplicateKeys = true;

  };

  # Because formats.generate is outputting a file, we use of conf-file. Once

  # `extraConfig` is deprecated we can just use

  # `dnsmasqConf = format.generate "dnsmasq.conf" cfg.settings`

  dnsmasqConf = pkgs.writeText "dnsmasq.conf" ''

    conf-file=${settingsFormat.generate "dnsmasq.conf" cfg.settings}

    ${cfg.extraConfig}

  '';

  dnsmasqConf = settingsFormat.generate "dnsmasq.conf" cfg.settings;

in

  imports = [

    (lib.mkRenamedOptionModule [ "services" "dnsmasq" "servers" ] [ "services" "dnsmasq" "settings" "server" ])

    (lib.mkRemovedOptionModule [ "services" "dnsmasq" "extraConfig" ] "This option has been replaced by `services.dnsmasq.settings`")

  ];

  ###### interface

        '';

      };

      extraConfig = lib.mkOption {

        type = lib.types.lines;

        default = "";

        description = ''

          Extra configuration directives that should be added to

          `dnsmasq.conf`.

          This option is deprecated, please use {option}`settings` instead.

        '';

      };

    };

  };

  config = lib.mkIf cfg.enable {

    warnings = lib.optional (cfg.extraConfig != "") "Text based config is deprecated, dnsmasq now supports `services.dnsmasq.settings` for an attribute-set based config";

    services.dnsmasq.settings = {

      dhcp-leasefile = lib.mkDefault "${stateDir}/dnsmasq.leases";

      conf-file = lib.mkDefault (lib.optional cfg.resolveLocalQueries "/etc/dnsmasq-conf.conf");

      servers = [

        "/${cfg.domain}/127.0.0.1#5300"

      ];

      extraConfig = ''

        bind-interfaces

        listen-address=127.0.0.1

      '';

      settings = {

        bind-interfaces = true;

        listen-address = "127.0.0.1";

      };

    };

  };