TCP probe support for socks proxy

[ptimofee]

HTTP probe has support for proxy via proxy_url config.
You can set it up to use http proxy like http://<fqdn_or_ip>:<port> or to use socks proxy like socks5://<fqdn_or_ip>:<port>

However there is no way to set proxy for TCP probe. Only socks would make sense for TCP.

This is a request to add TCP probe support for socks proxy