Readable AK times on details page

Before:

Dauer	Wann?	Raum
1,50	Sun 23:00	Internet

After:

Wann?	Dauer	Raum
Sun 23:00 - Mon 00:30	1:30	Internet

AKModel/models.py

@@ -336,6 +336,15 @@ class AKSlot(models.Model):
             return f"{self.ak} @ {self.start_simplified} in {self.room}"
         return f"{self.ak} @ {self.start_simplified}"
 
+    @property
+    def duration_simplified(self):
+        """
+        Display duration of slot in format hours:minutes, e.g. 1.5 -> "1:30"
+        """
+        hours = int(self.duration)
+        minutes = (self.duration * 60) % 60
+        return '%d:%02d' % (hours, minutes)
+
     @property
     def start_simplified(self):
         """
@@ -345,6 +354,21 @@ class AKSlot(models.Model):
             return _("Not scheduled yet")
         return self.start.astimezone(self.event.timezone).strftime('%a %H:%M')
 
+    @property
+    def time_simplified(self):
+        """
+        Display start and end time of slot in format weekday + time, e.g. "Fri 14:00 - 15:30" or "Fri 22:00 - Sat 02:00"
+        """
+        if self.start is None:
+            return _("Not scheduled yet")
+        result = self.start.astimezone(self.event.timezone).strftime('%a %H:%M')
+        result += ' - '
+        if self.start.astimezone(self.event.timezone).day == self.end.astimezone(self.event.timezone).day:
+            result += self.end.astimezone(self.event.timezone).strftime('%H:%M')
+        else:
+            result += self.end.astimezone(self.event.timezone).strftime('%a %H:%M')
+        return result
+
     @property
     def end(self):
         """