Fixes #18245: Make DeviceRole Hierarchical (#19008)

Made DeviceRoles hierarchical, had to also change the filtersets for Device, ConfigContext and VirtualMachine to use the TreeNodeMultipleChoiceFilter.

Note: The model was changed to use NestedGroupModel, a side-effect of this is it also adds comments field, but I thought that was better then doing a one-off just for DeviceRole and having to define the fields, validators, etc.. - keeps everything DRY / consistent.

* 18981 Make Device Roles Hierarchical

* 18981 forms, serializer

* 18981 fix tests

* 18981 fix tests

* 18981 fix tests

* 18981 fix tests

* 18981 fix tests

* 18981 fix migration merge

* 18981 fix tests

* 18981 fix filtersets

* 18981 fix tests

* 18981 comments

* 18981 review changes

netbox/dcim/forms/model_forms.py

@@ -431,17 +431,24 @@ class DeviceRoleForm(NetBoxModelForm):
         required=False
     )
     slug = SlugField()
+    parent = DynamicModelChoiceField(
+        label=_('Parent'),
+        queryset=DeviceRole.objects.all(),
+        required=False,
+    )
+    comments = CommentField()
 
     fieldsets = (
         FieldSet(
-            'name', 'slug', 'color', 'vm_role', 'config_template', 'description', 'tags', name=_('Device Role')
+            'name', 'slug', 'parent', 'color', 'vm_role', 'config_template', 'description',
+            'tags', name=_('Device Role')
         ),
     )
 
     class Meta:
         model = DeviceRole
         fields = [
-            'name', 'slug', 'color', 'vm_role', 'config_template', 'description', 'tags',
+            'name', 'slug', 'parent', 'color', 'vm_role', 'config_template', 'description', 'comments', 'tags',
         ]