admin can search ongoing sessions within a searching range

for #73359266
Professor @damithc, the one we had before is only a date picker and this one is a date time picker combined in one widget. And also the previous time picker is only picking time within limited (e.g. 1200H 1300H....) options but this dateTimePicker can pick more freely and the reason why I use this is because for admin may be it is better to have a more powerful dateTimePicker.