pbf/osm-file: move multipolygon tags from members to relation

Hi,

I want to pre-process downloaded OSM-data (big files) for my own use. Regarding relations, type=multipolygon, attributes should be removed from outer ways and go solely to the relation itself, like described in https://wiki.openstreetmap.org/wiki/Multipolygon_relation#Tagging.

I will probably try to use some Python and Osmosis calls to do that. Or do you know of simpler way?

Thanks, Redoute