add usage message and check for script 'import_consent.sh'

Currently usage example is written inside the script as a comment. Goal is to execute the script and let it validate the input, if valiation was not passed, reply with the usage as a message

Start with the script import_consent.sh and find the usage example currently written as a comment. Run the script with missing or invalid arguments to see current behavior, then add input validation that prints the usage message when validation fails. Done means invalid input returns the usage text instead of relying on the comment.

Scritto dal modello di indicizzazione a partire dal testo della issue.