Closes #19713: Enable recording user messages in the change log (#19908)

* Add message field to ObjectChange model

* Set max length on changelog message

* Enable changelog messages for single object operations

* Fix tests

* Add changelog message support for bulk edit & bulk delete

* Cosmetic improvements to form fields

* Fix bulk operation templates

* Add message support for bulk import/update

* Add REST API support for changelog messages (WIP)

* Fix changelog_message assignment

* Enable changelog message support for bulk deletions

* Add documentation

* Fix changelog message support for VirtualChassis

* Add ChangeLoggingMixin to necesssary model forms

* Introduce get_random_string() utility function for tests

* Incorporate changelog messages for object view tests

* Incorporate changelog messages for object bulk view tests

* Add missing mixins for changelog message support

* Tweak test to generate expected number of change records

* Finish adding tests for changelog message functionality

* Misc cleanup

* Fixes #19956: Prevent duplicate deletion records from cascading deletions

* Tweak bulk deletion test to work around cascading deletions issue

* Correct API URL

netbox/extras/api/serializers_/customlinks.py

@@ -1,14 +1,14 @@
 from core.models import ObjectType
 from extras.models import CustomLink
 from netbox.api.fields import ContentTypeField
-from netbox.api.serializers import ValidatedModelSerializer
+from netbox.api.serializers import ChangeLogMessageSerializer, ValidatedModelSerializer
 
 __all__ = (
     'CustomLinkSerializer',
 )
 
 
-class CustomLinkSerializer(ValidatedModelSerializer):
+class CustomLinkSerializer(ChangeLogMessageSerializer, ValidatedModelSerializer):
     object_types = ContentTypeField(
         queryset=ObjectType.objects.with_feature('custom_links'),
         many=True