Support sending sim data to MQTT

[neilenns]

Is your feature request related to a problem? Please describe.
It'd be so cool to take data from the sim and send it to an MQTT server for automation purposes.

Simple example: get the time of day from the sim and use it to control the brightness of your gaming room lights to match the actual outdoor brightness.

Describe the solution you'd like
MQTT as an output type

Additional context

Super basic proof of concept works. This would follow the same pattern as WebSockets and should be done after that work is merged.

[neilenns]

I have a branch with this working for outputs. It's pretty cool.