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.
URLs pointint to develop branch are a "moving picture" (in general any branch, but with develop there is even more potential evolution). Could it better to use a tagged version for this? (a tag version can not change, except if we explictely change the tag with git operations).