Migrate to fetch API, URLSearchParams and async-await

[simon04]

Use modern features:

• https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API
• https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams
• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await

[github-actions]

Size Change: -551 B (-3.34%)

Total Size: 16 kB

Filename	Size	Change
dist/Control.Geocoder.js	7.01 kB	-261 B (-3.59%)
dist/Control.Geocoder.modern.js	7.9 kB	-290 B (-3.54%)

ℹ️ View Unchanged

Filename	Size
dist/leaflet-control-geocoder.css	1.05 kB

_{compressed-size-action}

[mrAceT]

Is this why the following is no longer working?

L.Control.Geocoder.nominatim().geocode(address,function(results) {
    console.log(results);
});