[FEATURE] return `continent` for the geocoded results

[elgandoz]

Is your feature request related to a problem? Please describe. When I geocode a point, I also need to obtain the continent [Asia|Africa|North America|South America|Antarctica|Europe|Oceania]

Describe the solution you'd like Add continent to the returned results and to the type filter.

Describe alternatives you've considered Search within a custom built array of countries-continents pair or double geocode the point or country with another service (😥)

Additional context Oceania has a sort of blurred definition in some countries. There could be some inconsistencies for certain countries with overseas territories (Spain's Ceuta, French Polynesia and many similar cases). These are more of edge cases, and like with the regular geocoding, a standard needs to be found. https://en.wikipedia.org/wiki/Continent