Hardening/135

Implements the issue https://github.com/telefonicaid/fiware-connectors/issues/135

In addition to the `doc/operation/cygnus_01_to_0.*_migration.md` documents, the translation scripts have been modified in order a not sudoer user may run them.

Minor changes have been made in the translation scripts README and in the `doc/operation/ngsi2cosmos_migration.md` document, which references the translation docs.
What about cygnus_0.2_to_0.3_(or_higher)_migration.md ?