migrate examinations to generic model (and start adding mangament)

generic/migrations/0004_examination_modality.py

@@ -0,0 +1,19 @@
+# Generated by Django 4.1.4 on 2023-06-19 11:13
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('generic', '0003_remove_examination_modality'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='examination',
+            name='modality',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.SET_NULL, to='generic.modality'),
+        ),
+    ]