Fixes conference duration config to use valid IDNA.

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

                 certificate = "/etc/prosody/certs/jitmeet.example.com.crt";
         }
         speakerstats_component = "speakerstats.jitmeet.example.com"
-        conference_duration_component = "conference_duration.jitmeet.example.com"
+        conference_duration_component = "conferenceduration.jitmeet.example.com"
         -- we need bosh
         modules_enabled = {
             "bosh";
 Component "speakerstats.jitmeet.example.com" "speakerstats_component"
     muc_component = "conference.jitmeet.example.com"
 
-Component "conference_duration.jitmeet.example.com" "conference_duration_component"
+Component "conferenceduration.jitmeet.example.com" "conference_duration_component"
     muc_component = "conference.jitmeet.example.com"

resources/prosody-plugins/mod_conference_duration.lua

 local conference_duration_component
     = module:get_option_string(
-        "conference_duration_component", "conference_duration"..module.host);
+        "conference_duration_component", "conferenceduration"..module.host);
 
 module:add_identity("component", "conference_duration", conference_duration_component);