Overdue order notification (#3114)

* Adds a background task to notify users when a PurchaseOrder becomes overdue

* Schedule the overdue purchaseorder check to occur daily

* Allow notifications to be sent to "Owner" instances

- Extract user information from the Owner instance

* add unit test to ensure notifications are sent for overdue purchase orders

* Adds notification for overdue sales orders

* Clean up notification display panel

- Simplify rendering
- Order "newest at top"
- Element alignment tweaks

* style fixes

* More style fixes

* Tweak notification padding

* Fix import order

* Adds task to notify user of overdue build orders

* Adds unit tests for build order notifications

* Refactor subject line for emails:

- Use the configured instance title as a prefix for the subject line

* Add email template for overdue build orders

* Fix unit tests to accommodate new default value

* Logic error fix

InvenTree/plugin/builtin/integration/core_notifications.py

@@ -5,6 +5,7 @@ from django.utils.translation import ugettext_lazy as _
 
 from allauth.account.models import EmailAddress
 
+import common.models
 import InvenTree.tasks
 from plugin import InvenTreePlugin
 from plugin.mixins import BulkNotificationMethod, SettingsMixin
@@ -74,6 +75,14 @@ class CoreNotificationsPlugin(SettingsMixin, InvenTreePlugin):
             html_message = render_to_string(self.context['template']['html'], self.context)
             targets = self.targets.values_list('email', flat=True)
 
-            InvenTree.tasks.send_email(self.context['template']['subject'], '', targets, html_message=html_message)
+            # Prefix the 'instance title' to the email subject
+            instance_title = common.models.InvenTreeSetting.get_setting('INVENTREE_INSTANCE')
+
+            subject = self.context['template'].get('subject', '')
+
+            if instance_title:
+                subject = f'[{instance_title}] {subject}'
+
+            InvenTree.tasks.send_email(subject, '', targets, html_message=html_message)
 
             return True