NEW ORLEANS - As rock bands blasted and tailgate parties served up barbecue and brew, thousands of people poured into the streets Monday night, hoping to forget about Hurricane Katrina during a Mardi Gras-like celebration of the Saints’ first home game since the storm.Crowds swamped the area around the Louisiana Superdome in a human sea, creating a huge traffic jam for the team’s emotional return and the reopening of the stadium, which underwent $185 million in repairs to erase damage done during and after Katrina.“This is exactly what the city needs,” said Saints season ticket holder Clara Do