Fixed a bug in Discord Whitelist Integration.

Discord integration: remove from whitelist
Also setup steps are changed, so I'm gonna change description.

Two new /mcapwl params: bulkadd, bulkremove. You can type nicknames separated by comma to add all of them at one.

Did a little mistake.
P.S. please use config to toggle polling

This is my first plugin ever, so of course I can't do it normally without making 2 updates

1.16 and 1.17 support.
/invite customizable message. (messages: joindiscord)