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/filtersets.py

@@ -922,6 +922,29 @@ class DeviceRoleFilterSet(OrganizationalModelFilterSet):
         queryset=ConfigTemplate.objects.all(),
         label=_('Config template (ID)'),
     )
+    parent_id = django_filters.ModelMultipleChoiceFilter(
+        queryset=DeviceRole.objects.all(),
+        label=_('Parent device role (ID)'),
+    )
+    parent = django_filters.ModelMultipleChoiceFilter(
+        field_name='parent__slug',
+        queryset=DeviceRole.objects.all(),
+        to_field_name='slug',
+        label=_('Parent device role (slug)'),
+    )
+    ancestor_id = TreeNodeMultipleChoiceFilter(
+        queryset=DeviceRole.objects.all(),
+        field_name='parent',
+        lookup_expr='in',
+        label=_('Parent device role (ID)'),
+    )
+    ancestor = TreeNodeMultipleChoiceFilter(
+        queryset=DeviceRole.objects.all(),
+        field_name='parent',
+        lookup_expr='in',
+        to_field_name='slug',
+        label=_('Parent device role (slug)'),
+    )
 
     class Meta:
         model = DeviceRole
@@ -990,14 +1013,16 @@ class DeviceFilterSet(
         queryset=DeviceType.objects.all(),
         label=_('Device type (ID)'),
     )
-    role_id = django_filters.ModelMultipleChoiceFilter(
-        field_name='role_id',
+    role_id = TreeNodeMultipleChoiceFilter(
+        field_name='role',
         queryset=DeviceRole.objects.all(),
+        lookup_expr='in',
         label=_('Role (ID)'),
     )
-    role = django_filters.ModelMultipleChoiceFilter(
-        field_name='role__slug',
+    role = TreeNodeMultipleChoiceFilter(
         queryset=DeviceRole.objects.all(),
+        field_name='role',
+        lookup_expr='in',
         to_field_name='slug',
         label=_('Role (slug)'),
     )