Add Multi Port Traceroute test specification

TODO: fix https://github.com/TheTorProject/ooni-probe/issues/214
and provide example output of running test.
Add sample output of traceroute test
Merge branch 'feature/add_multi_port_traceroute_spec'

* feature/add_multi_port_traceroute_spec:
  Add sample output of traceroute test
  Add Multi Port Traceroute test specification