IFCExportOptions: set Classification Name and Classification field name from API

Hi @AngelVelezSosa and company,

Thanks for the work you are doing!

Using the exporter on Revit 20.2.30.42 from Python I am using the following exporting options to no effect:
```
options=IFCExportOptions()
options.AddOption("ClassificationName", classification_name)
options.AddOption("ClassificationFieldName", classification_parameter)
```
I cannot find any documentation for them, so I'm guessing they are bogus.
Currently, Classification field data is exported only when set from the UI, but I would like to enforce it from the API

Is it possible?

Thanks!

Start with IFCExportOptions.AddOption and the ClassificationName and ClassificationFieldName options shown in the issue, then compare their behavior with the Revit UI classification settings. The work is done when API-supplied values affect classification data in the exported IFC, or the supported API limitation is documented.

Written by the indexing model from the issue text.