Different server_version per port

[gerryd]

I have a specific use case, where I would need to advertise two different server_version values because of a client issue. Other than the server_version, everything else is the same.

I currently run two separate ProxySQL instances, with one on a non-standard port, but I was thinking it might be useful to be able to override specific settings per listening port. ProxySQL can already listen on multiple ports, though the port can only be used as a value in query rules later on.

Thanks for considering this!