[FEAT] New modes like country mode (states mode, continent mode, ...)

[BilelJegham]

Is your feature request related to a problem? Please describe.
GeoGuess has country mode. It should be great to have other game modes like states picker, continent picker.

Describe the solution you'd like

1. Allow users to create a new mode

   1. Define areas on the map with GeoJSON
      Examples :

• https://github.com/gregoiredavid/france-geojson/blob/master/regions-version-simplifiee.geojson
• https://gist.github.com/hrbrmstr/91ea5cc9474286c72838

2. add function set data random pos
   Ex:

export function getCountryCodeNameFromLatLng(latLng, errorFunction) {
   return axios
       .get(
           `https://nominatim.openstreetmap.org/reverse?lat=${latLng.lat()}&lon=${latLng.lng()}&zoom=5&addressdetails=1&format=json&extratags=1`
       )
       .then(({status, data}) => {
           if (status === 200 && data) {
               if(data.extratags['ISO3166-1:alpha2'])
                   return data.extratags['ISO3166-1:alpha2'];
               return data.address['country_code'].toUpperCase();
           }
       })
       .catch(() => {
           errorFunction();
           return undefined;
       });
}

3. Add function isPositionIsTrue

/**
* Return is area select is the right
* @param {object} propertyAreaSelect geojson feature property of the area select
* @param {LatLng} randomPos
* @return {boolean} true if is the right area
*/
function isPositionIsTrue(propertyAreaSelect, randomPos)

propertyAreaSelect  =  {"code":"93","nom":"Provence-Alpes-Côte d'Azur"}

Additional context
In the futures, we will save official modes on https://github.com/GeoGuess/GeoGuess-Maps

[BilelJegham]

When the user launches the game, test if box map played = box mode recommendation.

Exemple: Don't play world if area picker asset for french states ;)

[BilelJegham]

Implement in #194

Documentation available here : https://geoguess.games/guide/dev/areas.html