TANISHA HEIDEBERG and EMMA RUMNEY  IN an Italian bistro in an upmarket Johannesburg neighbourhood, smiling patrons chat at candle-lit tables in a scene reminiscent of less-troubled times before the COVID-19 pandemic. But there's no alcohol on the menu. Instead, diners order red or white "coffee" served in grey mugs, the tell-tale sign of a modern-day South African speakeasy. Under one of the world's strictest lockdowns, South Africa banned alcohol to lower hospital admissions for injuries from drink-related violence and accidents and ease the burden on healthworkers facing the worst coronavirus outbreak in Africa. But businesses from wine makers to restaurants…