Add Italian translations for verbs

[fquffio]

This PR adds Italian translations for the verbs.

The file verbs.min.js has been updated using Terser: terser --mangle verbs.js > verbs.min.js.

Note for Italian speakers

I'm a developer: I'm not a translator. These translations are definitely opinionated. I preferred standalone verbs to expressions that are more commonly used, and I omitted prepositions after the verb even where they would have made sense to stick with the convention used in other translations—I don't speak Spanish nor German, but I understand English and French, and it seems to me that the approach is similar.

Examples:

• «qlcu. ha preferito qlco.» instead of the more common «qlcu. ha aggiunto qlco. ai preferiti» (or «qlcu. ha aggiunto ai preferiti qlco.») because the former is shorter and because the latter is not strictly a "verb", but rather a "verb + complement".

  Other examples: «qlcu. ha progredito qlco.» vs. «qlcu. ha fatto progressi con/in qlco.», «qlcu. ha ottenuto qlco.» vs. «qlcu. ha ottenuto un punteggio di/in qlco.».

• «qlcu. ha risposto qlco.» instead of «qlcu. ha risposto a qlco.» to be more concise—this is not actually the same difference as "so. answered sth." versus "so. answered to sth.", because in Italian the former would sound much weirder, but that gives you an idea.

  Other examples: «qlcu. ha interagito qlco.» vs. «qlcu. ha interagito con qlco.», «qlcu. ha assistito qlco.» vs. «qlcu. ha assistito a qlco.», «qlcu. ha rinunciato qlco.» vs. «qlcu. ha rinunciato a qlco.».

• «qlcu. ha registrato qlco.» instead of the more likely to be correct «qlcu. si è registrato a qlco.» because the first is in the active form, the latter being passive. Since xAPI verbs are meant to be in the active form, I used «ha registrato» even though it would be more appropriate as the translation of the English verb "recorded", not "registered".

Other weirdos:

• «ha padroneggiato» is rarely used, except in cases like a competition where one of the opponents outclassed the others.
• «ha sperimentato» is more commonly used for "experimented" rather than "experienced", but «ha fatto esperienza» is weirder and much more ambiguous, so I preferred the first.