Handle construction tags

In TILDA we started rewriting construction tags. The idea being, that we want to handle them like the original object they are knowing that they are just temporary.

We could do the same in Speedwalk and it would IMO make sense for the same reason.

However, the difference with TILDA is, that we have to consider the export and upload case. The upload has to use the original OSM tags. So an easy overwrite like we do with TILDA is out and we would need to handle separate tag lists instead and decide which one to use where.
- For Uplaod we want the original tags of course
- But for Export I see reasons for both – depending on the data usage

This was too complex for a quick fix, so lets leave it here to hear what other think…