feat: Module to hide rooms for some queries.

doc/debian/jitsi-meet-prosody/prosody.cfg.lua-jvb.example

     restrict_room_creation = true
     storage = "memory"
     modules_enabled = {
+        "muc_hide_all";
         "muc_meeting_id";
         "muc_domain_mapper";
         "polls";
     restrict_room_creation = true
     storage = "memory"
     modules_enabled = {
+        "muc_hide_all";
         "muc_meeting_id";
         "muc_domain_mapper";
         "muc_rate_limit";
 Component "internal.auth.jitmeet.example.com" "muc"
     storage = "memory"
     modules_enabled = {
+        "muc_hide_all";
         "ping";
     }
     admins = { "focusUser@auth.jitmeet.example.com", "jvb@auth.jitmeet.example.com" }
     muc_room_locking = false
     muc_room_default_public_jids = true
     modules_enabled = {
+        "muc_hide_all";
         "muc_rate_limit";
         "polls";
     }

resources/prosody-plugins/mod_muc_hide_all.lua

+-- This module makes all MUCs in Prosody unavailable on disco#items query
+-- Copyright (C) 2023-present 8x8, Inc.
+
+module:hook("muc-room-pre-create", function(event)
+    event.room:set_hidden(true);
+end, -1);