members/models: moved head count calculations inside freizeit model

jdav_web/members/admin.py

@@ -925,10 +925,10 @@ class MemberOnListInline(CommonAdminInlineMixin, GenericTabularInline):
     def people_count(self, obj):
         if isinstance(obj, Freizeit):
             # Number of organizers who are also in the Memberlist
-            organizer_count = len(obj.staff_on_memberlist)
+            organizer_count = obj.staff_on_memberlist_count
 
             # Total number of people in the Memberlist
-            total_people = obj.participant_count + organizer_count
+            total_people = obj.head_count
             
         else: # fallback if no activity was found
             total_people = 0

jdav_web/members/models.py

@@ -1146,12 +1146,20 @@ class Freizeit(CommonModel):
         jls = set(self.jugendleiter.distinct())
         return ps.intersection(jls)
     
+    @property
+    def staff_on_memberlist_count(self):
+        return len(self.staff_on_memberlist)
+
     @property
     def participant_count(self):
         ps = set(map(lambda x: x.member, self.membersonlist.distinct()))
         jls = set(self.jugendleiter.distinct())
         return len(ps - jls)
     
+    @property
+    def head_count(self):
+        return self.staff_on_memberlist_count + self.participant_count
+
     @property
     def approved_staff_count(self):
         """Number of approved youth leaders for this excursion. The base number is calculated