Communication: Create EthernetPacketizer

This code previously was separately maintained in each of the
PCAP driver layers.

While adding complexity for reassembly, I decided it was
time to pull it out into a common implementation.

As of this commit, the old implementations have not been
removed from the PCAP drivers yet.

CMakeLists.txt

@@ -124,6 +124,7 @@ set(SRC_FILES
 	communication/packet/ethernetpacket.cpp
 	communication/decoder.cpp
 	communication/encoder.cpp
+	communication/ethernetpacketizer.cpp
 	communication/packetizer.cpp
 	communication/multichannelcommunication.cpp
 	communication/communication.cpp