Translate the bsdl-gpl article in Italian
Suggestion for commit message:
```
it_IT/articles/bsdl-gpl: Add Italian translation
Submitted by: Lorenzo Salvadore <salvadore@FreeBSD.org>
Reviewed by: ???
Obtained from: https://translate-dev.freebsd.org/
Differential Revision: https://reviews.freebsd.org/D23598
```