[TIMOB-27425] Add Time-Based Option to Alert Sending for Geographic Selection

With the upcoming changes to iOS 13 regarding Location services, particularly the Always Allow location services I would like to make an improvement selection for sending Alerts on Appcelerator when choosing Geographic Selection. Since most apps will be moving away from Always Allow there are very few times when an app will be able to report the user leaving a location since they will have already backgrounded the app in most cases. Here is an example use case: A user attends a festival for which they already have the app for the event. They get to the event and open it to check the schedule. At that time we could update the users location to Appcelerator's servers. Even without Always Allow we could continue to update the users location while the app is open and then after is closed for a few more minutes. The problem is that we would not know when the user left the festival since the app is already backgrounded and our last reported location for them on the Appcelerator server says they are still there. But if there was an option to send to everyone within a radius of the festival who reported their location within the last XX minutes (maybe 15 minutes for example) then the Geographic Selection push notification alerts still serve a purpose. Without this feature I'm afraid it will not be as useful as you will be sending to a group of users who are false-reporting that they are currently at the festival. I've mocked up what this could look like when sending an alert using Geographic Location.