JAVA SDK FTS query: unsupported Geospatial query coordinate format: Geohash

For now we have just one way to create Coordinate instance for different types of Geospatial queries:

public static Coordinate ofLonLat(double lon, double lat) {

    return new Coordinate(lon, lat);

}

According to official Couchbase Server documentation 

https://docs.couchbase.com/server/current/fts/fts-geospatial-queries.html

we need to support another coordinate format: Geohash

https://en.wikipedia.org/wiki/Geohash

Coyrresponding query looks like this:

"polygon_points": [

  "9q8zjbkp",

  "9q8yvvdh",

  "9q8yyp1e",

  "9q8yyrw8",

  "9q8zn83x",

  "9q8zjb0j"

]