Store Ifc class in attribute

This shouldn't be necessary ? but it's easier for now

src/blenderbim/blenderbim/bim/helper.py

@@ -115,6 +115,7 @@ def import_attribute(attribute, props, data, callback=None):
     description = get_attribute_description(data["type"], attribute.name())
     if description:
         new.description = description
+    new.ifc_class = data["type"]
 
 
 def export_attributes(props, callback=None):

src/blenderbim/blenderbim/bim/prop.py

@@ -259,6 +259,7 @@ def update_attribute_value(self, context):
 class Attribute(PropertyGroup):
     name: StringProperty(name="Name")
     description: StringProperty(name="Description")
+    ifc_class: StringProperty(name="Ifc Class")
     data_type: StringProperty(name="Data Type")
     string_value: StringProperty(name="Value", update=update_attribute_value)
     bool_value: BoolProperty(name="Value", update=update_attribute_value)