bug#52345: Add the new packages section to the Italian tutorial

[Stefan Kangas]

close 52345 29.1
thanks

Lele Gaifax <lele@metapensiero.it> writes:

> * etc/tutorials/TUTORIAL.it (INSTALLAZIONE DI ULTERIORI PACCHETTI):
>   Translate from recently added INSTALLING PACKAGES section in the
>   English version.
>   (CONCLUSIONI): Reword paragraph, to better convey the original
>   intent.

Thanks for the patch!  Pushed to master as commit 6e50d86ca2.