lemmy-know: Send notifications when Lemmy reports are made through Discord or as MQTT message

I made this tool some time ago to respond quicker to reports which didn't federate to the instance of my main account (lemmy.world). Previously I would have to check from multiple instances daily, and now I get a notification on my phone when a report is made within a couple of minutes. I cleaned it up a little and added some documentation in case anyone else is dealing with this issue or needs something like this.