Implement ability to add BCF header file

src/ifcblenderexport/blenderbim/bim/__init__.py

@@ -35,6 +35,7 @@ if bpy is not None:
         operator.EditBcfTopic,
         operator.SaveBcfProject,
         operator.AddBcfTopic,
+        operator.AddBcfHeaderFile,
         operator.ViewBcfTopic,
         operator.RemoveBcfComment,
         operator.EditBcfComment,
@@ -45,6 +46,7 @@ if bpy is not None:
         operator.RemoveBcfFile,
         operator.OpenUri,
         operator.OpenBcfReferenceLink,
+        operator.SelectBcfHeaderFile,
         operator.SelectFeaturesDir,
         operator.SelectDiffJsonFile,
         operator.SelectDiffNewFile,