Support date changes

[bretwalker]

Court dates often move, so it would be good to support checking to see if a date has moved before sending an alert.

If a date moves further into the future, CourtBot can simply re-check the date before sending an alert, and schedule a new reminder, if necessary.

Code for Kentuckiana is working on setting up a stateless proxy to Kentucky court data. In this case, CourtBot could call the proxy with a stored case number (and other necessary info) before sending a previously-scheduled alert. It sounds like CourtBot may need to store some additional info so that it can re-request information before sending out a reminder.

If a date gets moved up, this process won't work, because the alert and check wouldn't be scheduled to occur until the original court date. We should talk to partners in the court system to find out how often this actually happens and what the process is. I feel like there would be an existing notification process in this case, so CourtBot may not need to account for it (or it could be designed in the future).