Add srt.rate.pkts, srt.rate.Mbps, srt.bw.pkts, srt.bw.Mbps columns to UMSG_ACK dataframe

[mbakholdina]

The calculation is currently being done in the following script. Move this logic to the library and update mentioned script once implemented.

[mbakholdina]

Not sure, whether it is a good idea to implement this in a library. The main goal of the library is to parse tshark dump, extract the packets of interest and the data of interest. There should no processing on top of the extracting data except formatting and stuff.