misc/mtail: Start of an mtail config Stashing it here in case anyone wants to continue working on it. Currently it's only counting log messages by level. Due to the permissions set by systemd on Prosody logs, mtail never managed to start correctly until permissions were manually relaxed.

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.