More work

- Consolidated "in_stock" filter to single code location
- Improve 'limit_choices_to' for BuildItem and SalesOrderAllocation
- Various template improvements etc

InvenTree/order/migrations/0030_auto_20200426_0551.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.5 on 2020-04-26 05:51
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0033_auto_20200426_0539'),
+        ('order', '0029_auto_20200423_1042'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='salesorderallocation',
+            name='item',
+            field=models.ForeignKey(help_text='Select stock item to allocate', limit_choices_to={'belongs_to': None, 'build_order': None, 'customer': None, 'part__salable': True}, on_delete=django.db.models.deletion.CASCADE, related_name='sales_order_allocations', to='stock.StockItem'),
+        ),
+    ]

InvenTree/order/migrations/0031_auto_20200426_0612.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.5 on 2020-04-26 06:12
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0034_auto_20200426_0602'),
+        ('order', '0030_auto_20200426_0551'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='salesorderallocation',
+            name='item',
+            field=models.ForeignKey(help_text='Select stock item to allocate', limit_choices_to={'belongs_to': None, 'build_order': None, 'part__salable': True, 'sales_order': None}, on_delete=django.db.models.deletion.CASCADE, related_name='sales_order_allocations', to='stock.StockItem'),
+        ),
+    ]