With slow foot traffic amid a gentle drizzle of rain, Amorino—a “boutique” gelato shop—quietly opened its doors in Harvard Square earlier this week. The high-end dessert establishment is the second Amorino site in the greater Boston area, joined by a location on Newbury Street that opened in 2015. Léa Sasportes, the executive developer for Amorino in Massachusetts and Rhode Island, said in an interview in late May she had sought to open a Harvard Square location since before the Newbury location opened, noting the chain’s popularity among students and tourists.