Add "external" field to StockLocation (#4377)

* Add "external" field to StockLocation

- New model for field
- Database migrations
- Serializer / API updates
- Front end tables / filters

* Update API version

InvenTree/stock/migrations/0095_stocklocation_external.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.18 on 2023-02-20 12:22
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0094_auto_20230220_0025'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='stocklocation',
+            name='external',
+            field=models.BooleanField(default=False, help_text='This is an external stock location', verbose_name='External'),
+        ),
+    ]