make 'name' unique in space for MealType

make MealType, Unit, Supermarket, Supermarket Category, PropoertyType
case insenstive for get_or_create
convert unit conversion create serializer to get_or_create behavior
enable create duplicate tests for unitconversion and mealtype api

cookbook/migrations/0203_alter_unique_contstraints.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.5 on 2023-09-14 12:26
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cookbook', '0202_remove_space_show_facet_count'),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name='mealtype',
+            constraint=models.UniqueConstraint(fields=('space', 'name'), name='mt_unique_name_per_space'),
+        ),
+    ]