Nick Vivarelli International CorrespondentIn Italian director Francesco Lettieri’s “Lovely Boy,” which is the closing film of Venice’s independently run Venice Days section, a rising star of Rome’s never before depicted trap music scene gets sucked into a spiral of self-destruction.“Lovely Boy” is the sophomore feature by Lettieri, who made his debut with “Ultras,” a drama about Neapolitan soccer hooligans that plays worldwide on Netflix.Both “Ultras” and “Lovely Boy” were lead produced by