Improve logging

[sbernard31]

This issue aims to centralize all possible amelioration about current logging facilities (#22):

• use the python logging facilities instead of print
• logging level should also impact python output (not only bpf one)
• currently in log we only show MAC/IP, maybe it would make more sense to show MAC/IP:port
  when possible.
• add support of syslog, maybe using sysloghandler
• bpf log could show if packet is DROP, PASS, TX.
• use macro for bpf logging instead of if to improve performance ? we should first find a way to measure performance !

[oliwer]

Also, we will need to send the production logs to Loggly using syslog. It should be easy to add a "SyslogHandler" to the python logger.

[sbernard31]

Also, we will need to send the production logs to Loggly using syslog. It should be easy to add a "SyslogHandler" to the python logger.

I add it to the list.