PAS-20: Mail Handling

TLS connections to mail servers are already captured, but plaintext aren't.

I haven't decided yet on exactly what information should be extracted, but a starting point would be to start building something similar to webtraffic.csv so there's a record of which mailservers were connected to (and EHLO names etc)

PAS-15 is interested in extracting SMTP Plain authentication strings, so it'd be helpful if the tempfile also included those somehow, as it'd save doing a seperate tshark run.