Refactoring

* splits ema/models.py into subpackage
* splits konova/models.py into subpackage
* splits user/models.py into subpackage

user/models/konova_user.py

@@ -0,0 +1,19 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: michel.peltriaux@sgdnord.rlp.de
+Created on: 15.11.21
+
+"""
+from django.contrib.auth.models import User
+from django.db import models
+
+
+class KonovaUserExtension(models.Model):
+    """ Extension model for additional ksp features
+
+    Extends the default user model for some extras
+
+    """
+    user = models.OneToOneField(User, on_delete=models.CASCADE)
+    notifications = models.ManyToManyField("user.UserNotification", related_name="+")