Move "getAvailableStockItems" to the build model

InvenTree/build/migrations/0026_auto_20201023_1228.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.0.7 on 2020-10-23 12:28
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0052_stockitem_is_building'),
+        ('build', '0025_auto_20201020_1248'),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name='builditem',
+            unique_together={('build', 'stock_item', 'install_into')},
+        ),
+    ]