Create working template for the new blocks page

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

@@ -151,6 +151,13 @@ export class ApiService {
       );
   }
 
+  getBlocks$(from: number): Observable<BlockExtended[]> {
+    return this.httpClient.get<BlockExtended[]>(
+      this.apiBasePath + this.apiBasePath + `/api/v1/blocks-extras` +
+      (from !== undefined ? `/${from}` : ``)
+    );
+  }
+
   getHistoricalDifficulty$(interval: string | undefined): Observable<any> {
     return this.httpClient.get<any[]>(
         this.apiBaseUrl + this.apiBasePath + `/api/v1/mining/difficulty` +