Start package for automating conference call lights turning on

[technicalpickles]

This is the first pass at conference call automation. It relies on https://github.com/technicalpickles/isthisthingon running on my laptop to publish to mqtt. The response time is pretty good, it turns on and off pretty quickly.

There's some room for improvement:

• use hue scenes instead of homeassistant ones? could use named ones like energize and reading.
• remember the previous state of the lights. be smarter about what to do when going off conference call, since that would mean turning off the light and potentially leaving me in the dark