Though open for only a few weeks, Salvatore's restaurant in Medford shows much promise.  It is located at 55 High Street, the former site of the Depositor's Trust Bank, notorious for an incident back in 1980 when police officers were among a crew that broke into the vault over Memorial Day weekend.  The restaurant has turned the vault into a museum about this incident.  I dropped by for dinner and found a good-sized restaurant with a lengthy, oval bar. The large front windows look out onto High Street and near the front of the restaurant is a fireplace surrounded by comfortable chairs and a …