add a physical connecion attribute at the port level

since we do not supprot a route resolution involving passive farmes (i.e Patch Panels, Matrix), we cannot create a physical connection from a DUT into the PP interchassis and establish routes going thorugh them.

therefore, we need to have a "physical connection" attribute on the port level of the DUT and PP in order to hold the connection data for future reference

in use at DT an TI
