nixos/knot: add release notes and partial compatibility

- `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`.

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

- `mariadb` now defaults to `mariadb_1011` instead of `mariadb_106`, meaning the default version was upgraded from 10.6.x to 10.11.x. See the [upgrade notes](https://mariadb.com/kb/en/upgrading-from-mariadb-10-6-to-mariadb-10-11/) for potential issues.

      };

    };

  };

  imports = [

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

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

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

    )

  ];

  config = mkIf config.services.knot.enable {

    users.groups.knot = {};