Revert "You can now override custom category element functions in IfcFM"

This reverts commit 8a63275db0.

src/ifcfm/ifcfm/__init__.py

@@ -48,7 +48,6 @@ class Parser:
         self.preset = preset
         self.categories = {}
         self.config = None
-        self.get_custom_category_elements = {}
         self.get_custom_element_data = {}
         self.duplicate_keys = []
 
@@ -61,11 +60,7 @@ class Parser:
     def parse(self, ifc_file, name=None):
         for category_name, category_config in self.config["categories"].items():
             self.categories.setdefault(category_name, {})
-            if category_name in self.get_custom_category_elements:
-                elements = self.get_custom_category_elements[category_name](ifc_file)
-            else:
-                elements = category_config["get_category_elements"](ifc_file)
-            for element in elements:
+            for element in category_config["get_category_elements"](ifc_file):
                 get_element_data = category_config["get_element_data"]
 
                 if isinstance(get_element_data, dict):