Ordered m2m for Inventory/Inventory relationship (#13602)

Including changes to our custom Ordered m2m field which previously broke
if the source and target model was the same.

Signed-off-by: Rick Elrod <rick@elrod.me>
Co-authored-by: Alan Rominger <arominge@redhat.com>

awx/main/migrations/0182_constructed_inventory.py

@@ -1,6 +1,8 @@
 # Generated by Django 3.2.16 on 2022-12-07 14:20
 
+import awx.main.fields
 from django.db import migrations, models
+import django.db.models.deletion
 
 
 class Migration(migrations.Migration):
@@ -9,13 +11,27 @@ class Migration(migrations.Migration):
     ]
 
     operations = [
+        migrations.CreateModel(
+            name='InventoryConstructedInventoryMembership',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('position', models.PositiveIntegerField(db_index=True, default=None, null=True)),
+                (
+                    'constructed_inventory',
+                    models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main.inventory', related_name='constructed_inventory_memberships'),
+                ),
+                ('input_inventory', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main.inventory')),
+            ],
+        ),
         migrations.AddField(
             model_name='inventory',
             name='input_inventories',
-            field=models.ManyToManyField(
+            field=awx.main.fields.OrderedManyToManyField(
                 blank=True,
+                through_fields=('constructed_inventory', 'input_inventory'),
                 help_text='Only valid for constructed inventories, this links to the inventories that will be used.',
                 related_name='destination_inventories',
+                through='main.InventoryConstructedInventoryMembership',
                 to='main.Inventory',
             ),
         ),