As at 6 June 2023, what number of schools (a) in the Republic and (b) in each province (i) use only (aa) plain pit and bucket latrines and (bb) ventilated improved pit (VIP) latrines and (ii) have (aa) plain pit and bucket latrines and other sanitation facilities on their premises and (bb) VIP latrines and other sanitation facilities on their premises?