Currently, to_chat is literally just a proc that does user << message.
But it'll let us do output modification in the future, especially for
something like Goon's HTML chat.
Big thanks to PJB for his to_chat script, see
https://github.com/d3athrow/vgstation13/pull/6625 for more details.
This commit changes every 'world.log <<' message with a loggable proc-
log_to_dd().
This is adjustable in the config; If LOG_WORLD_OUTPUT is present, all
things sent to world.log will show up in the standard /data/logs/ logs.
These logs will contain the following (in order):
Timestamp
"DD_OUTPUT:"
The message.
The config option for this, by default, is turned off.
