Filter out 'stale' requests
Non-closed old timeslots showed up because the checkForUpcomingRequestsSlot
function only filtered upwards of the starting time of a slot.
By adding a lower bound for the filter on slot.opensAt, requests from longer than 1 day ago should no longer show up.
Additional changes:
- A log message telling the time is removed as it did not any necessary information.
- An unused field for a datetime format is removed.
Closes #189 (closed)