Last week, Paris shooed cars from its downtown for a single photogenic day. Now a neighborhood in Johannesburg, South Africa is one-upping that car-free day with a celebration that kicks cars off the street for the entire month of October. As part of the EcoMobility World Festival, which started today, cars have been banished from Sandton, the central business district of the city and often known as the “richest square mile” in Africa due to…