Added empty classes for collection and property types

Author: JosePizarro3

bam_data_store/datamodel/property_types.py

@@ -127,3 +127,11 @@ def model_validator_after_init(cls, data: Any) -> Any:
                 data.terms.append(attr)
 
         return data
+
+
+class PropertyType(BaseEntity):
+    pass
+
+
+class CollectionType(BaseEntity):
+    pass