Closes #19891: Bulk operation jobs (#19897)

* Add background_job toggle to BulkEditForm

* Account for bug fix in v4.3.4

* Enable background jobs for bulk edit & bulk delete

* Move background_job field to a mixin

* Cosmetic improvements

* Misc cleanup

* Fix BackgroundJobMixin

netbox/utilities/forms/mixins.py

@@ -6,11 +6,20 @@ from django.core.validators import MaxValueValidator, MinValueValidator
 from django.utils.translation import gettext_lazy as _
 
 __all__ = (
+    'BackgroundJobMixin',
     'CheckLastUpdatedMixin',
     'DistanceValidationMixin',
 )
 
 
+class BackgroundJobMixin(forms.Form):
+    background_job = forms.BooleanField(
+        label=_('Background job'),
+        help_text=_("Execute this task via a background job"),
+        required=False,
+    )
+
+
 class CheckLastUpdatedMixin(forms.Form):
     """
     Checks whether the object being saved has been updated since the form was initialized. If so, validation fails.