README-IT translation update

Hello this is my first experience at contributing to an Open Source project, please don't be too harsh with me.

I would like to update italian translation README-IT.md

Italian is my mother tongue and i would like to update the current Italian translation

i plan to:

• add missing links from the updated README.md english version
• add missing sections from the updated README.md english version
• improving translation if i spot any translation error that can be fixed

thank you in advance for your help, and suggestions ^_^