Clockwise from top left: on Via Libertini, cycling by Porta Rudiae, detail of Basilica di Santa Croce, the beach in San Cataldo and Trattoria di Nonna Tetti.CreditCreditGianni Cipriano for The New York Times Thanks to dozens of mostly Baroque-era churches packing its maze of narrow streets, Lecce, the “Florence of the South,” dazzles with…