- DBManager preserves the basic methods, while the appointment related ones have been moved to AppointmentDBM.
- AppointmentDBM handles json loads and dumps for appointments and trackers, so the corresponding methods can be removed from their classes.
- Updates docs.
Appointment serialization used to be part of the cryptographer (signature_format) but it makes more sense to be an appointment method. Therefore cli also need Appointment
Also fixes comments based on reviews