Add utility to log&ban IPs

We can't ban IPs on TCP tasks because the Load Balancer terminates the TCP connections for us. So while we can limit (to some degree) the traffic we receive, we don't have enough visibility to know where the traffic comes from.

To make that work we need to enable https://cloud.google.com/load-balancing/docs/tcp/setting-up-tcp#proxy-protocol

This could be a simple container that just forwards packets internally and logs IPs. Blocking can be done as NetPol rules.