DiscordSRV Commands Extension 1.0

First release of DiscordSRV Commands Extension.
Adds 6 slash commands to discord:
/whitelist add | username | discord-user(optional) - add a user to the whitelist and optionally link their discord account
/whitelist list - list players on the whitelist
/whitelist remove | username - remove a player from the whitelist
/restart - restart the server
/stop - stop the server
/list - list online players (returns an ephemeral message)

This plugin has only been tested on Purpur 1.20.4