This commit introduces a new public api in uhd::utils which allows serializing
and deserializing chdr packets.
As far as testing, this commit adds the chdr_parse_test test. It uses a
wireshark trace located in rfnoc_packets_*.cpp as well as hand coded
packets from hardcoded_packets.cpp to test the serialization and
deserialization process
Signed-off-by: Samuel O'Brien <sam.obrien@ni.com>
