ENH: get the classification system from the property name

### Enhancement Description

Currently, the IFC exporter allows multiple classifications via ClassificationName(n) format, where the value must meet certain formatting, according to [(https://wiki.osarch.org/index.php?title=Revit_setup_for_OpenBIM/Revit_IFC_classifications)]

The proposal would allow ClassificationName[name] format, eg. ClassificationNameCCI, where "CCI" is the name of the classification. Therefore, the format of the field value could be simplified to [key]{:name} format, eg, "BB" or "BB:Foundation structure"

### Revit Version

2024.0.x

### IFC for Revit Addon Version

24.x.x

### Windows Version

10 22H2

No file or test is named. Start by searching the IFC exporter for handling of ClassificationName(n) and the existing classification value format; the work is done when ClassificationName[name] and key:name values are accepted while existing classification behavior remains supported.

Written by the indexing model from the issue text.