Better docs in monitoringHisto
Better docs in monitoringHisto

- Add date format to use with -s and -e parameters in documentation

SmartInfrastructures/FIWARELab-monitoringAPI,SmartInfrastructures/FIWARELab-monitoringAPI,attybro/xifi-monitoringAPI,attybro/FIWARELab-monitoringAPI,SmartInfrastructures/FIWARELab-monitoringAPI