Refactor packet dump to be done from packets received from pjsip

[MayamaTakeshi]

Currently we use libpcap to do this by updating a filter every time we create a SIP/RTP endpoint. However there are problems with this approacy:

• this doesn't permit to get all TCP/TLS traffic as if we connect to a remove SIP server, a random local port will be used (we will have only the traffic that reaches us with our listeing TCP/TLS ports).
• in case of TLS we need to handle SSL keys to be able to decode the messages

Instead, let's dump the messages according to what is received from pjsip: all SIP messages and RTP traffic would be dumped as UDP no matter how they were received/sent. (obs: not sure if we can actually do this yet).

[MayamaTakeshi]

Based on some tests, packet dump is not even currently working.

We can adapt code from here: https://github.com/asterisk/asterisk/blob/master/res/res_hep_pjsip.c Ref: https://asteriskfaqs.org/2017/01/03/asterisk-users/does-hep-require-pjsip-or-does-it-also-works-with-sip.html

[MayamaTakeshi]

Using HEP we can send the messages to sngrep and see the call flows in real-time.