Split platforms with multiple DHIDs

[Robbendebiene]

Some platforms provide boarding places on both sides. Mappers sometimes then split these platforms in the middle into 2 platform elements to separate tags like ref. Others keep them as one element and instead add multiple values for the same tag. Example: https://www.openstreetmap.org/relation/3264414#map=18/52.12995/11.62747

For the DHID this looks like this:
ref:IFOPT=de:XXX;de:YYY

We should simply create two OSM elements out of this. They will have the same geometry and same tags, except when multiple values exist. Biggest challenge is how to handle their OSM ids, since keeping the id is important to reference them for relations and the like. It might be possible to stop using the ids as primary keys.