[Refactor] Notification plugins (#9735)

* Refactor notification concept

- Notifications handled by plugins

* Cleanup

* Only send email if template provided in context

* Logic cleanup

* Fix log_error call

* Refactor error logging

- Ensure plugin slug is correctly attached
- Consistent format
- Logic fixes

* More robust plugin lookup

* Refactor calls to tringger_notification

* Tweak for build stock notification

* Low stock notification refactor

- Actually *use* the notification system
- Fix for email template

* Check stock only when build is issued

* Updated documentation

* Add PluginUserSetting class

- Allows plugins to define per-user settings

* Add API endpoints for PluginUserSetting model

* Placeholder for user-plugin-settings page

* Refactoring frontend code

* Placeholder panel

* Adds user interface for changing user-specific plugin settings

* Tweaks

* Remove old model

* Update documentation

* Playwright tests

* Update API version

* Fix unit test

* Fix removed arg

* Fixes for email notifications

- Track status of sending notifications
- Add helper "activate" method for plugin class
- Update unit tests

* Fix barcode tests

* More unit test fixes

* Test fixes

* Fix for settings models with extra fields

* Enhance unit test

* Remove old test file

* Check for null target_fnc

* Improve DB query efficiency

- Provide a flat list of active keys to plugin.is_active
- Prevents DB fetching (in certain circumstances)
- Add registry.active_plugins() method

* Bump query limit up for test

- In practice, this API endpoint is ~10 queries

* Handle potential errors

* Increase query limit for API test

* Increase query limit for some tests

* Bump API version

* Tweak unit test

* Tweak unit test

* Increased allowed queries

* fix user plugin settings

* Fix for unit test

* Update debug msg

* Tweak API

* Fix endpoint

* Remove "active plugin keys" code

* Restore previous behaviour

* Fix unit tests

* Tweak unit test

* Update src/backend/InvenTree/build/tasks.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/backend/InvenTree/plugin/base/integration/NotificationMixin.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Func updates

* Format

* Add notification settings

* Refactor plugin settings groups

* Fix func type

* Adjust message

* Additional unit tests

* Additional playwright tests

* Additional playwright test

---------

Co-authored-by: Matthias Mair <code@mjmair.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

docs/mkdocs.yml

@@ -227,6 +227,7 @@ nav:
       - Label Printing Mixin: plugins/mixins/label.md
       - Locate Mixin: plugins/mixins/locate.md
       - Navigation Mixin: plugins/mixins/navigation.md
+      - Notification Mixin: plugins/mixins/notification.md
       - Report Mixin: plugins/mixins/report.md
       - Schedule Mixin: plugins/mixins/schedule.md
       - Settings Mixin: plugins/mixins/settings.md
@@ -238,24 +239,30 @@ nav:
       - Label Printer: plugins/machines/label_printer.md
     - Builtin Plugins:
       - Builtin Plugins: plugins/builtin/index.md
-      - Auto Create Builds: plugins/builtin/auto_create_builds.md
-      - Auto Issue: plugins/builtin/auto_issue.md
-      - BOM Exporter: plugins/builtin/bom_exporter.md
-      - Currency Exchange: plugins/builtin/currency_exchange.md
-      - InvenTree Barcode: plugins/builtin/inventree_barcode.md
-      - InvenTree Exporter: plugins/builtin/inventree_exporter.md
-      - Label Printer: plugins/builtin/inventree_label.md
-      - Label Machine: plugins/builtin/inventree_label_machine.md
-      - Label Sheet: plugins/builtin/inventree_label_sheet.md
-      - Notification: plugins/builtin/notifications.md
-      - Parameter Exporter: plugins/builtin/part_parameter_exporter.md
-      - Part Notifications: plugins/builtin/part_notifications.md
       - Barcode Plugins:
         - Barcode Plugins: plugins/builtin/barcode_index.md
+        - InvenTree Barcode: plugins/builtin/inventree_barcode.md
         - DigiKey Barcode Plugin: plugins/builtin/barcode_digikey.md
         - LCSC Barcode Plugin: plugins/builtin/barcode_lcsc.md
         - Mouser Barcode Plugin: plugins/builtin/barcode_mouser.md
         - TME Barcode Plugin: plugins/builtin/barcode_tme.md
+      - Event Plugins:
+        - Auto Create Builds: plugins/builtin/auto_create_builds.md
+        - Auto Issue: plugins/builtin/auto_issue.md
+        - Part Update Notification: plugins/builtin/part_notifications.md
+      - Export Plugins:
+        - BOM Exporter: plugins/builtin/bom_exporter.md
+        - InvenTree Exporter: plugins/builtin/inventree_exporter.md
+        - Parameter Exporter: plugins/builtin/part_parameter_exporter.md
+      - Label Printing:
+        - Label Printer: plugins/builtin/inventree_label.md
+        - Label Machine: plugins/builtin/inventree_label_machine.md
+        - Label Sheet: plugins/builtin/inventree_label_sheet.md
+      - Notification Plugins:
+        - Email Notifications: plugins/builtin/email_notification.md
+        - Slack Notifications: plugins/builtin/slack_notification.md
+        - UI Notifications: plugins/builtin/ui_notification.md
+      - Currency Exchange: plugins/builtin/currency_exchange.md
     - Third-Party: plugins/integrate.md
 
 # Plugins