Deprecate onion v2 endpoints

[anadahz]

This is issue is about deprecating v2 onion endpoints.

[francisco-core]

Tor browser's latest update removes v2 addresses support. I guess it's time to ditch these.

https://blog.torproject.org/v2-deprecation-timeline

[anadahz]

We don't expose the onion v2 endpoints on https://privacylx.org .