Hide blank fields in string representation of ConstraintViolation and add edit link for each violation on constraint violation overview

This fixes #130 (closed)

AKModel/models.py

@@ -2,6 +2,7 @@ import itertools
 from datetime import timedelta
 
 from django.db import models
+from django.urls import reverse_lazy
 from django.utils import timezone
 from django.utils.datetime_safe import datetime
 from django.utils.text import slugify
@@ -539,6 +540,10 @@ class ConstraintViolation(models.Model):
     def details(self):
         return self.get_details()
 
+    @property
+    def edit_url(self):
+        return reverse_lazy('admin:AKModel_constraintviolation_change', kwargs={'object_id': self.pk})
+
     @property
     def level_display(self):
         return self.get_level_display()