Created|Deleted refactoring

* refactors base attributes created and deleted into UserActionLogEntry foreign keys
* refactors all related queries and process logic
* fixes binding_on into binding_date in intervention/detail/view.html
* adds basic __str__ for some models
*

intervention/models.py

@@ -12,6 +12,7 @@ from django.utils import timezone
 from django.utils.timezone import now
 
 from intervention.settings import INTERVENTION_IDENTIFIER_LENGTH, INTERVENTION_IDENTIFIER_TEMPLATE
+from konova.enums import UserActionLogEntryEnum
 from konova.models import BaseObject, Geometry, UuidModel
 from konova.utils import generators
 from konova.utils.generators import generate_random_string
@@ -30,6 +31,13 @@ class ResponsibilityData(UuidModel):
     conservation_file_number = models.CharField(max_length=1000, blank=True, null=True)
     handler = models.CharField(max_length=500, null=True, blank=True, help_text="Refers to 'Eingriffsverursacher'")
 
+    def __str__(self):
+        return "ZB: {} | ETS: {} | Handler: {}".format(
+            self.registration_office,
+            self.conservation_office,
+            self.handler
+        )
+
 
 class LegalData(UuidModel):
     """
@@ -44,6 +52,13 @@ class LegalData(UuidModel):
     process_type = models.CharField(max_length=500, null=True, blank=True)
     law = models.CharField(max_length=500, null=True, blank=True)
 
+    def __str__(self):
+        return "{} | {} | {}".format(
+            self.process_type,
+            self.law,
+            self.id
+        )
+
 
 class Intervention(BaseObject):
     """
@@ -121,13 +136,20 @@ class Intervention(BaseObject):
         with transaction.atomic():
             # "Delete" related compensations as well
             coms = self.compensations.all()
+            action = UserActionLogEntry.objects.create(
+                user=_user,
+                timestamp=_now,
+                action=UserActionLogEntryEnum.DELETED.value
+            )
             for com in coms:
-                com.deleted_on = _now
-                com.deleted_by = _user
+                com.deleted = action
+                #com.deleted_on = _now
+                #com.deleted_by = _user
                 com.save()
 
-            self.deleted_on = _now
-            self.deleted_by = _user
+            self.deleted = action
+            #self.deleted_on = _now
+            #self.deleted_by = _user
             self.save()
 
     @staticmethod