The Louvre Museum reopened to the public Saturday, less than 24 hours after a machete-wielding assailant shouting “Allahu akbar!” attacked French soldiers guarding the sprawling building and was shot by them. The worldwide draw of the iconic museum in central Paris, host to thousands of artworks including the “Mona Lisa,” was on full display on a drizzly winter day as international tourists filed by armed police and soldiers patrolling outside the site, which had been closed immediately after Friday’s attack.