* Allow changing the broadcasted port using a system property. This may be needed if the port Geyser runs on & the port Bedrock players connect on do not match - e.g. due to port forwarding/different routing.
* initial stab at making the broadcast port an (unsafe) config option
* Automatically set broadcast port to be the bind port unless manually overridden
* Warn about broadcast port mismatch
* Use 0 instead of -1 as indicator to broadcast the port geyser is running on