Implement export of AK conflicts and dependencies

This adds the information on AK dependencies and conflicts to the JSON export. Both information are added in the properties dict.

AKModel/models.py

@@ -966,7 +966,6 @@ class AKSlot(models.Model):
                 "conflicts": [str(conflict.pk) for conflict in conflict_slots.all()],
                 "dependencies": [str(dep.pk) for dep in dependency_slots.all()],
             },
-            "properties": {},
             "room_constraints": [constraint.name
                                  for constraint in self.ak.requirements.all()],
             "time_constraints": ["resolution"] if self.ak.reso else [],