updates bosh to support optional prefix

use optional prefix in poltergeist room lookup

resources/prosody-plugins/mod_auth_token.lua

         local params = formdecode(query);
         session.auth_token = query and params.token or nil;
 
-        -- The room name from the bosh query
+        -- The room name and optional prefix from the bosh query
         session.jitsi_bosh_query_room = params.room;
+        session.jitsi_bosh_query_prefix = params.prefix or "";
     end
 end);
 

resources/prosody-plugins/mod_muc_poltergeist.lua

     if (session.jitsi_meet_context_user) then
         local room = get_room(
             session.jitsi_bosh_query_room,
-            session.jitsi_meet_domain);
+            session.jitsi_bosh_query_prefix);
 
         if (not room) then
             return nil;