[feat] OSM-Integration for places

As of now, I have no idea how to use the current locationsystem in gancio. We are trying to build a rally calendar for the whole germanspeaking area and the system - as it is now - is not usable for us.

Would it be possible to add openStreetMap support? The adress field could have autocomplete from OSM, the locationmanagement could be removed and a small mapwidget could be provided.

further links: