Add referer header to Nominatim requests

Per the [Nominatim usage policy][1], all requests should have an
identifying Referer or User-Agent header (quoted below). Using the host
name, as we already do for Mapbox requests, should be sufficient to
satisfy the requirement while avoiding the need for additional settings.

> Provide a valid HTTP Referer or User-Agent identifying the
> application (stock User-Agents as set by http libraries will not do).

[1]: https://operations.osmfoundation.org/policies/nominatim/

Author: bplubell

src/services/GeoService.php

@@ -796,7 +796,15 @@ private static function _latLngFromAddress_Nominatim ($address, $country): ?arra
 				$url .= '&country=' . rawurlencode($country);
 		}
 
-		$data = (string) static::_client()->get($url)->getBody();
+		$referer = Craft::$app->getRequest()->getIsConsoleRequest()
+			? Craft::getAlias('@web')
+			: Craft::$app->urlManager->getHostInfo();
+
+		$data = (string) static::_client()->get($url, [
+			'headers' => [
+				'referer' => $referer
+			]
+		])->getBody();
 		$data = Json::decodeIfJson($data);
 
 		if (!is_array($data) || empty($data))
@@ -883,7 +891,15 @@ private static function _addressFromLatLng_Nominatim ($lat, $lng): ?array
 		$url .= '&accept-language=' . Craft::$app->locale->getLanguageID();
 		$url .= '&lat=' . rawurlencode($lat) . '&lon=' . rawurldecode($lng);
 
-		$data = (string) static::_client()->get($url)->getBody();
+		$referer = Craft::$app->getRequest()->getIsConsoleRequest()
+			? Craft::getAlias('@web')
+			: Craft::$app->urlManager->getHostInfo();
+
+		$data = (string) static::_client()->get($url, [
+			'headers' => [
+				'referer' => $referer
+			]
+		])->getBody();
 		$data = Json::decodeIfJson($data);
 
 		if (!is_array($data) || empty($data) || array_key_exists('error', $data))