Sync missing attribute translations from OSM

[entorb]

Hi, running your great app in German language on iOS, I found some attributes not being translated yet (e.g. house->type->detached or garages). My proposal would be to sync translations from OSM instead of manually re-translating them.

As far as I know, the translations are managed here
https://github.com/openstreetmap/iD/blob/develop/CONTRIBUTING.md#translating

Maybe that way you could easily add all OSM languages to your app, see #376

Is this would be too much effort, I am volunteering for manually translating the missing ones, if you would provide me a list.