empty topologies created by framework

[mgheorghe]

ports get assigned with empty config
either we should not use those ports if they don't bring any value or if they are needed they need to be configured.

dentos_testbed_runtests -d --stdout \
  --config ./DentOsTestbed/configuration/testbed_config/sit/testbed5.json \
  --config-dir ./DentOsTestbed/configuration/testbed_config/sit/ \
  --suite-groups suite_group_traffic_tests \
  --discovery-reports-dir ./reports \
  --discovery-path ./DentOsTestbedLib/src/dent_os_testbed/discovery/modules/