[Standards] mailing list simplification

Hi all, The XSF infrastructure team is planning to move our mailman installation from a dedicated machine to a cloud service. In preparation for doing so, I have just deleted three lists that are no longer in use: iot(a)xmpp.org security(a)xmpp.org server-developers(a)xmpp.org If IOT or security topics arise, they can be discussed on this list or in the xsf(a)muc.xmpp.org chatroom. Peter