mod_pubsub_post: Allow specifying item id by a special mapping If `{http://jabber.org/protocol/pubsub}id` exists as an attribute at the top level then it is used, otherwise the previous behavior (.id if string)

This module produces more detailed HTTP logs for Prosodys built-in HTTP
server. The format is similar to that of Apache and go into Prosodys
normal logs at the `info` level.