Add LN node per country graph

frontend/src/app/services/api.service.ts

@@ -262,4 +262,8 @@ export class ApiService {
   getNodeForISP$(isp: string): Observable<any> {
     return this.httpClient.get<any[]>(this.apiBaseUrl + this.apiBasePath + '/api/v1/lightning/nodes/isp/' + isp);
   }
+
+  getNodesPerCountry(): Observable<any> {
+    return this.httpClient.get<any[]>(this.apiBaseUrl + this.apiBasePath + '/api/v1/lightning/nodes/countries');
+  }
 }