Build API for tree/planter country

Currently, we don't have the API to show the country of the location, like for a tree and planter.
We need build a API to get the country (it would be better if we can also get the city or province in the country like the picture shows) by giving the coordinates(lat/lon)

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Some hints:
* Please read our [readme](https://github.com/Greenstand/treetracker-web-map-client#treetracker-web) for more information/guide/tutorial.
* Here is [an engineering book](https://greenstand.gitbook.io/engineering/) in Greenstand.
* To know more about our organization, visit our [website](https://greenstand.org).