Merge #258361: nixos/knot: compatibility with 23.05 config

- `pass` now does not contain `password-store.el`.  Users should get `password-store.el` from Emacs lisp package set `emacs.pkgs.password-store`.

- `services.knot` now supports `.settings` from RFC42.  The change is not 100% compatible with the previous `.extraConfig`.

- `services.knot` now supports `.settings` from RFC42.  The previous `.extraConfig` still works the same, but it displays a warning now.

- `mu` now does not install `mu4e` files by default.  Users should get `mu4e` from Emacs lisp package set `emacs.pkgs.mu4e`.

  in result;

  configFile = if cfg.settingsFile != null then

    assert cfg.settings == {} && cfg.keyFiles == [];

    # Note: with extraConfig, the 23.05 compat code did include keyFiles from settingsFile.

    assert cfg.settings == {} && (cfg.keyFiles == [] || cfg.extraConfig != null);

    cfg.settingsFile

  else pkgs.writeTextFile {

  else

    mkConfigFile yamlConfig;

  mkConfigFile = configString: pkgs.writeTextFile {

    name = "knot.conf";

    text = (concatMapStringsSep "\n" (file: "include: ${file}") cfg.keyFiles) + "\n" + yamlConfig;

    text = (concatMapStringsSep "\n" (file: "include: ${file}") cfg.keyFiles) + "\n" + configString;

    # TODO: maybe we could do some checks even when private keys complicate this?

    checkPhase = lib.optionalString (cfg.keyFiles == []) ''

      ${cfg.package}/bin/knotc --config=$out conf-check

        description = lib.mdDoc ''

          As alternative to ``settings``, you can provide whole configuration

          directly in the almost-YAML format of Knot DNS.

          You might want to utilize ``writeTextFile`` for this.

          You might want to utilize ``pkgs.writeText "knot.conf" "longConfigString"`` for this.

        '';

      };

    };

  };

  imports = [

    # Compatibility with NixOS 23.05.  At least partial, as it fails assert if used with keyFiles.

    # Compatibility with NixOS 23.05.

    (mkChangedOptionModule [ "services" "knot" "extraConfig" ] [ "services" "knot" "settingsFile" ]

      (config: pkgs.writeText "knot.conf" config.services.knot.extraConfig)

      (config: mkConfigFile config.services.knot.extraConfig)

    )

  ];