Closes #13428: Q-in-Q VLANs (#17822)

* Initial work on #13428 (QinQ)

* Misc cleanup; add tests for Q-in-Q fields

* Address PR feedback

netbox/virtualization/migrations/0042_vminterface_vlan_translation_policy.py

@@ -1,5 +1,3 @@
-# Generated by Django 5.0.9 on 2024-10-11 19:45
-
 import django.db.models.deletion
 from django.db import migrations, models
 

netbox/virtualization/migrations/0043_qinq_svlan.py

@@ -0,0 +1,28 @@
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ipam', '0075_vlan_qinq'),
+        ('virtualization', '0042_vminterface_vlan_translation_policy'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='vminterface',
+            name='qinq_svlan',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='%(class)ss_svlan', to='ipam.vlan'),
+        ),
+        migrations.AlterField(
+            model_name='vminterface',
+            name='tagged_vlans',
+            field=models.ManyToManyField(blank=True, related_name='%(class)ss_as_tagged', to='ipam.vlan'),
+        ),
+        migrations.AlterField(
+            model_name='vminterface',
+            name='untagged_vlan',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='%(class)ss_as_untagged', to='ipam.vlan'),
+        ),
+    ]