Eden Health grdn.routes.impl.appointments API

Contains handlers for routes related to Appointments, Cases, Encounters etc. On timezones: Appointments are tied to Athena departments, and their date and start time are to be interpreted as representing a local datetime in the Athena department's time zone. Popups are special in that they have a dedicated department with the New York time zone, but their physical location (and thus time zone) could differ from that. To abstract over departments and popups, we introduce the notion of a location time zone, that is equal to the pop-up's time zone for popup appointments, and the department time zone for all others. All appointment times for appointments at physical locations are displayed to the user in the location time zone. All appointment times for virtual appointments are displayed to the user in their preferred time zone as communicated by the client.