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.
Ok.

However, what are the main differences between 0.1 to 0.2 and 0.2 to 0.3 migration? (the .md file seems to be mostly the same... maybe I'm missing subtle details; just curiority BTW :))