The Wikivoyage geo template should automatically pull data from the associated Wikidata item, instead of requiring the community to maintain its own set of coordinates for each page. What is the best way to implement this? Something like:

• {{geo}} -- if wikidata has coordinates, make it into a map icon link with default zoom (?), otherwise, do nothing
• {{geo|zoom=10}} -- if wikidata has coordinates, make it into a map icon link with the given zoom, otherwise, do nothing
• {{geo|10|20|zoom=10}} -- will override wikidata's values, but will add a hidden category indicating that wikidata has / doesn't have these coordinates, and that the geo template overrides it. Those categories can be used by bots to copy coordinates to wikidata, or to erase them in the template if needed.