Add data check system

Related to AlekSIS-App-Alsijil#91 (closed)

aleksis/core/data_checks.py

 import logging
 
+from django.contrib.contenttypes.models import ContentType
 from django.db.models.aggregates import Count
 from django.utils.translation import gettext as _
 
@@ -44,6 +45,16 @@ class DataCheck:
         with reversion.create_revision():
             cls.solve_options[solve_option].solve(check_result)
 
+    @classmethod
+    def register_result(cls, instance) -> "DataCheckResult":
+        from aleksis.core.models import DataCheckResult
+
+        ct = ContentType.objects.get_for_model(instance)
+        result = DataCheckResult.objects.get_or_create(
+            check=cls.name, content_type=ct, object_id=instance.id
+        )
+        return result
+
 
 class DataCheckRegistry:
     def __init__(self):