xmppophone #7278867 adapt conf commands to use same id as internal conf number [in-progress]

Actually join/invite conf command to 3000 doesn't mean joining the same conf as "3000" internal conf number. Adapt this command to go to the same conf may be a great improvement.

done in1.0
closed by<not specified>
patch[fscnx] adapt conf command to use same room as internal numbered room [in-progress]