[Feature Request] Add Pattern VALID_NICK to the configuration file

[jojoto]

Currently the regex pattern that verifies the user's nickname is hard-coded in PlayerKickListeners.java would it be possible to place it in the configuration file to be able to modify it more easily. https://github.com/nickuc/OpeNLogin/blob/29431f9a6980f28e598fb036d320fdfd64a3f8c7/openlogin-bukkit/src/main/java/com/nickuc/openlogin/bukkit/listener/PlayerKickListeners.java#L29

Currently i have a Geyser & Floodgate plugin on a server and by default a dot is added to users to avoid playername conflicts.

ps: I also noticed that after changing the prefix given by Floodgate. The login message stays on the screen forever for bedrock users, the player has to go in the Nether for it to disappear.