Metrics response disaggregation based on Rx ports

[anjan-keysight]

We require support for drill down of stats based on Rx ports when we support multi Rx port device (and raw) traffic. Currently we are aggregating port level stats and only segregate at flow and egress tracking level.
Secondly we need model support for specifying Tx Rx ratio for loss calculation, where there is mismatch between Tx and Rx frames based on DUT configuration (eg Tx frames may get replicated across all Rx ports, and we get 4x packets at flow level).