Swagger: https://rdvmairie-optimisation-dev.osc-secnum-fr1.scalingo.io/docs
* RendezVous models are now soft-deleted through the canceled datetime
field when specifically stated as 'annule' on the
rendez-vous-disponible endpoint or when absent from a full update,
* last-upload timestamp field on the RendezVous model allow filtering of
created/updated RendezVous instances to push,
* new configuration keys are added to store the authentication token and
base URL of the new API endpoints.
* new command upload-rdvs is run every 3 minutes by uwsgi cron to push
new/deleted rendez-vous into the ANTS database.
* soft-deleted rendez-vous are excluded from aggregated statistics on
active rendez-vous
* Tests added for success and error path in ants_hub.api.ants routines.