feat: add add-role component (#494)

Fixes: #487

src/app/system/system.service.ts

@@ -39,6 +39,14 @@ export class SystemService {
     return this.http.get('/roles');
   }
 
+  /**
+   * @param {any} role Role to be created.
+   * @returns {Observable<any>}
+   */
+  createRole(role: any): Observable<any> {
+    return this.http.post('/roles', role);
+  }
+
   /**
    * @returns {Observable<any>} Fetches Codes.
    */