Option to enable NAT support for IPv4 session traffic

[jmtoms]

Is your feature request related to a problem? Please describe.

When I run bng blaster the with IPv4 session traffic enabled, with NAT in DUT configured, not all sessions are being verified.

"session-traffic": {
    "ipv4-pps": 1
}

Currently blaster console shows following because the downstream flow destination is private IP Address (not the NAT IP Address) and the packet is being dropped at DUT WAN (due to no NAT session)

Traffic Flows Verified                                                                                                                                                           
  Session            1/2

Describe the solution you'd like

I would like to have a feature that is similar to traffic stream, an option to enable NAT support. For example:

"session-traffic": {
    "ipv4-pps": 1,
    "nat": true
}

Additional context

Bng Blaster 0.9.26 on Ubuntu amd64. Trying to test NAT support in DUT.

Thanks,
JT