Add in-memory sniffing

[AleksaMCode]

• Sniffing changed from time-based file capture to in-memory packet capture.
  • Sniffer is no longer starting subprocess with airodump-ng in order to capture packets and store them in a *.cap file.
• pyshark is removed, as there is no more need to parse *.cap files.
  • Packets are parsed in-memory, as soon as they are captured.

[!CAUTION] In order to use scapy, sniffer needs to be run with sudo command. Potentially, running a Python interpreter as root could be dangerous.