[Request] Add cvar for custom in-game chat message prefix

[kmak7]

When you send message from discord it gets displayed on server with prefix of discords channel name it was sent from e.g.

[game-chat] user: hello

Allow us to change the prefix to custom one instead taking discord channel name. Some can be confused and not understand where messages are coming from. I would like to just set prefix so messages read like this

[Discord] user: hello

I can change channel name on discord to achieve this but then it's confusing for people on discord what this #discord channel is

edit: doesn't need to be cvar can be a setting in relay server config