[Plugins] Cloudflare DNS plugin

**Is your feature request related to a problem? Please describe.**
Lobby server can start on a random port. A system that can change dns entries should be perfect.

**Describe the solution you'd like**
A plugin that creates dns SRV entries for all servers and groups.
For example:
bedwars.myserver.net or a root myserver.net pointing to a group like lobby.