feat(dcim): Add device, module and rack count filters

Introduces `device_count`, `module_count` and `rack_count` filters to
enable queries based on the existence and count of the associated
device, module or rack instances.
Updates forms, filtersets, and GraphQL schema to support these filters,
along with tests for validation.

Fixes #19523

netbox/dcim/models/modules.py

@@ -13,8 +13,10 @@ from extras.models import ConfigContextModel, CustomField
 from netbox.models import PrimaryModel
 from netbox.models.features import ImageAttachmentsMixin
 from netbox.models.mixins import WeightMixin
+from utilities.fields import CounterCacheField
 from utilities.jsonschema import validate_schema
 from utilities.string import title
+from utilities.tracking import TrackingModelMixin
 from .device_components import *
 
 __all__ = (
@@ -92,6 +94,10 @@ class ModuleType(ImageAttachmentsMixin, PrimaryModel, WeightMixin):
         null=True,
         verbose_name=_('attributes')
     )
+    module_count = CounterCacheField(
+        to_model='dcim.Module',
+        to_field='module_type'
+    )
 
     clone_fields = ('profile', 'manufacturer', 'weight', 'weight_unit', 'airflow')
     prerequisite_models = (
@@ -186,7 +192,7 @@ class ModuleType(ImageAttachmentsMixin, PrimaryModel, WeightMixin):
         return yaml.dump(dict(data), sort_keys=False)
 
 
-class Module(PrimaryModel, ConfigContextModel):
+class Module(TrackingModelMixin, PrimaryModel, ConfigContextModel):
     """
     A Module represents a field-installable component within a Device which may itself hold multiple device components
     (for example, a line card within a chassis switch). Modules are instantiated from ModuleTypes.