nixos-module/defaults: remove journalbeat

the service caused excessive disk write traffic, and the target greylog
server is overloaded anyway.

nix/nixos-module/defaults.nix

@@ -19,33 +19,6 @@
     Storage=volatile
   '';
 
-  # central logging
-  services.journalbeat = {
-    enable = true;
-    tags = [ "zentralwerk" ];
-    extraConfig = ''
-      journalbeat.inputs:
-        # Paths that should be crawled and fetched. Possible values files and directories.
-        # When setting a directory, all journals under it are merged.
-        # When empty starts to read from local journal.
-        - paths: []
-      journalbeat:
-        seek_position: cursor
-        cursor_seek_fallback: tail
-        write_cursor_state: true
-        cursor_flush_period: 5s
-        clean_field_names: true
-        convert_to_numbers: false
-        move_metadata_to_field: journal
-        default_type: journal
-        kernel: true
-      output.logstash:
-        # Boolean flag to enable or disable the output module.
-        enabled: true
-        hosts: ["${config.site.net.serv.hosts4.logging}:5044"]
-    '';
-  };
-
   nix = {
     package = pkgs.nixFlakes;
     extraOptions = "experimental-features = nix-command flakes";