Add new port forwarding mode to `cro3 dut shell` or other command

[mhiramat]

It is useful to support local port forwarding from DUT if the DUT is in the different network.

cro3 dut shell --forward 12345:123.45.67.89:1234 --dut mydut

Or, maybe we can add monitor option

cro3 dut monitor mydut,123.45.67.89:1234,123.45.67.90:1234

In this case, the forwarded port is automatically decided by cro3.