(feature suggestion) add broadcast, venturechat commands to the Velocity version of the plugin

[RalphORama]

It would be nice to have broadcast available in Velocity so one could send messages to all servers on the network through the proxy.

My use case for this is: I run my servers using Pterodactyl and use the panel's schedule functionality to restart the proxy server twice a week. On my Paper servers, I send broadcast commands to let players know about upcoming restarts. It would be nice to be able to do the same with the Velocity server itself (i.e. broadcast The proxy server is restarting in 5 minutes!)

Additionally, it would be nice to have access to commands like venturechat to quickly check plugin info on the proxy.