Hong Kong’s health authorities have set up more than 100 community testing centres for mass Covid-19 screening and will launch an online registration process for the drive on Saturday, as the city is expecting another 13 coronavirus cases on Friday.Government officials on Friday unveiled details of the mass testing scheme due to begin on September 1, and urged residents to sign up for it from 7am on Saturday.“For yourself, your loved ones, our hardworking medical staff and the wider community,…