Make specifying FTS geo coordinates less error-prone

Suggested release note:

Coordinates in Full-Text Search geographic queries can now be specified using a staged builder, so it's harder to accidentally swap the latitude and longitude components. Example usage:

Coordinate eiffelTower = Coordinate.lat(48.858093).lon(2.294694);

Or, if you prefer to specify longitude first:

Coordinate eiffelTower = Coordinate.lon(2.294694).lat(48.858093);