Sniffer should use ScapySocket
Currently the function capturePackets in ooni/utils/net.py defers to a thread the scapy sniff() function.
This is not ideal since we have ooni/utils/txscapy.py that is made for using the scapy super socket file descriptor in a non-blocking way.
the capturePackets function should be refactored to use ScapyProtocol in ooni/utils/txscapy.py