Add more cipher/TLS version issue detection

Adds on_ssl to data handlers (previously we only called it on connection handlers to decide if we should attempt a MiTM) and adds insecurecipherdetection and weaktlsversiondetection.

Currently for insecure ciphers we check for anon ciphers(no authentication) or NULL ciphers(no encryption).

For versions we detect SSLv2 and SSLv3 as being weak.