feature: Proxy Support

[tirz]

Add a simple SOCKS5 proxy support with tokio-socks.

We must enable the proxy feature:

let config = Config {
    ...
    proxy_type: Some(ProxyType::Socks5),
    proxy_server: Some("127.0.0.1".to_owned()),
    proxy_port: Some(1080),
    ..Default::default()
};

Also, set use_ssl to true by default - avoiding MTIM attacks because of misconfigurations.