[5.x] Update and fix strings translation for Italian language

[gioppy]

Update and fix all strings translated with Google Translate in Italian.

[vitalijalbu]

@gioppy @jasonvarga wanted to say that "PRO" (next to the logo of the navbar) is also translated in italian with "Professionale", that in my opinion PRO should be equal for all languages..

[gioppy]

Tecnically you have right, Pro will be translated as "Professionale", but in this case the logo on the navbar will be too long, so i prefer the simple and slim "Pro"!

[jasonvarga]

This PR changes it to just Pro which I think is good. I didn't notice Professionale when I ran Google Translate on everything. 👌

[ghost]

This PR changes it to just Pro which I think is good. I didn't notice Professionale when I ran Google Translate on everything. 👌

heah, basically i think PRO can stay as non-translated string... for all languages.. 👀

[jasonvarga]

I initially thought so too, but we made it translatable for languages that don't use English characters, like Persian or Arabic. They would still use "Pro" (and even "Statamic") but it would be written phonetically using their alphabet.