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_/configtemplates.py

@@ -1,6 +1,6 @@
 from core.api.serializers_.data import DataFileSerializer, DataSourceSerializer
 from extras.models import ConfigTemplate
-from netbox.api.serializers import ValidatedModelSerializer
+from netbox.api.serializers import ChangeLogMessageSerializer, ValidatedModelSerializer
 from netbox.api.serializers.features import TaggableModelSerializer
 
 __all__ = (
@@ -8,7 +8,7 @@ __all__ = (
 )
 
 
-class ConfigTemplateSerializer(TaggableModelSerializer, ValidatedModelSerializer):
+class ConfigTemplateSerializer(ChangeLogMessageSerializer, TaggableModelSerializer, ValidatedModelSerializer):
     data_source = DataSourceSerializer(
         nested=True,
         required=False