[2020] Change 24-hour duration to 23

Thanks, @sail0r , it is a great suggestion. I am going to let the devs know once more to consider this. I cannot promise anything, as this suggestion comes every now and then.

While 23h mechanics are great, it is part of balance keeping to have also 21 hours ones (Spire set), as well as 24 and 12-hour collection, although 23 flows better, meaning that it is possible that some buildings will have to stay at 12/24 hours. However, I will bring it up again to them.