Move apps in main directory

Signed-off-by: Emmy D'Anello <emmy.danello@animath.fr>

registration/migrations/0003_alter_participantregistration_zip_code.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.13 on 2023-01-16 22:13
+
+import django.core.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('registration', '0002_auto_20230110_2031'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='participantregistration',
+            name='zip_code',
+            field=models.PositiveIntegerField(validators=[django.core.validators.MinValueValidator(1000), django.core.validators.MaxValueValidator(99999)], verbose_name='zip code'),
+        ),
+    ]