Support different IP/hostname for UDP and TCP ports

[MPV]

Is your feature request related to a problem? Please describe.

I'm running my servers (including SourceBans++) in Kubernetes, and due to a current limitation there, it's not possible to have the same external IP for the UDP and TCP ports being exposed (if you're curious, see https://github.com/kubernetes/kubernetes/pull/75831).

For example HLstatsXCE supports having a separate "public ip/hostname" for a server (compared to the sometimes private RCON port):

Describe the solution you'd like

Separate IP for RCON and game server ports. I.e. a different address for the join server links.

Describe alternatives you've considered

Today I must add my servers using the TCP port so RCON integration works, but join links don't work, since I don't expose the same server on the UDP port on that hostname/IP.

Additional context

Example of how HLstatsX CE does it:

[rumblefrog]

This is a pretty edge case scenario. Wouldn't it be better to wait for the upstream fix? It looks like it's already done and waiting to resolve the conflicts.

[MPV]

Despite there being a pull-request for it, it's unclear if and when that change will make it there. Currently there's been requests for creating a "KEP" (Kubernetes Enhancement Proposal) for that change first.

Looking at it again now, there seems to be some potential workarounds there though. I'll review and see if I can get any of those to work.