Add GESIS Server at Hetzner Online GmbH to federation

[rgaiacs]

Related to #3264

In #3265, @yuvipanda said

Hetzner's network abuse policy is that we must respond and take action often within 48 or 72h, or they will simply stop all network traffic to the server. So, I think we must have project access before we can take this into rotation.

cc @arnim

[rgaiacs]

I will merge this. It replaces the old GESIS server with the new GESIS server. It uses a weight of 5 to avoid the container registry to be overwhelm. I will later increase the weight.