By Gavin Jones ROME (Reuters) – Diana Parini left her waitressing job at an Italian Alpine resort last month because she was fed up with the pay and conditions: eight euros per hour, of which six were paid cash-in-hand with no welfare or pension contributions. Parini, 44, who has a modern languages degree, went home to Milan to work as a dogsitter. Millions of others have similar stories in Italy, where much work is unregulated and – uniquely in Europe – wage growth has been stagnant for 30 years. With consumer prices surging across the euro zone, there are signs wages are also climbing – but …