nixos/networkd-dispatcher: use writeShellScript to ease use (#370347)

    services.networkd-dispatcher.extraArgs =

      let

        scriptDir = pkgs.symlinkJoin {

          name = "networkd-dispatcher-script-dir";

          paths = lib.mapAttrsToList (

        scriptDir = pkgs.runCommand "networkd-dispatcher-script-dir" { } (

          ''

            mkdir $out

          ''

          + (lib.concatStrings (

            lib.mapAttrsToList (

              name: cfg:

            (map (

              state:

              pkgs.writeTextFile {

              (lib.concatStrings (

                map (state: ''

                  mkdir -p $out/${state}.d

                  ln -s ${

                    lib.getExe (

                      pkgs.writeShellApplication {

                        inherit name;

                        text = cfg.script;

                destination = "/${state}.d/${name}";

                executable = true;

                      }

            ) cfg.onState)

          ) cfg.rules;

        };

                    )

                  } $out/${state}.d/${name}

                '') cfg.onState

              ))

            ) cfg.rules

          ))

        );

      in

      [

        "--verbose"