hydra-proxy: replace abuse handling with anubis

[mweinelt]

Closes: #626

[jfly]

LGTM!

style nit, feel free to ignore: I personally like using nix to inject config.services... references to port numbers rather than hardcoding the port number everywhere.

[mweinelt]

The issue with that is that the BIND variable is a go style bind which can reference a path, a port (:3000) or an ip/port combo.

[SuperSandro2000]

Shouldn't we limit that to Prometheus and not make it public?

[mweinelt]

Eventually, but up until now all exporters have been publically accessible.

[SuperSandro2000]

That is not that great.

Depending on the exporter this might be more or less of a problem. Some just expose internal counters but others execute commands on scrape and I am not sure if they have rate limit and if you could cause damage by spamming those endpoints.