Add utility to log&ban IPs

[sirdarckcat]

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.

[sirdarckcat]

https://cloud.google.com/vpc/docs/flow-logs#gke-external-lb-flows seems to imply there are connection logs

[sirdarckcat]

there are, they need to be enabled https://cloud.google.com/vpc/docs/using-flow-logs#gcloud with --enable-flow-logs on the subnet creation. we use gke to create the subnet, so we maybe have to "update" the subnet once created. we probably wanna do a high aggregation rate and a low sampling as to avoid using too much logging space.