text: Title: [Request] Allow repeated k-fold cross validation
  Body: In order to reduce overfitting, I would like to ask for a new parameter: "n_repetitions". This parameter sets the number of complete sets of folds to compute for repeated k-fold cross-validation.
  
  Cross-validation example:
  ```
  {
      "validation_type": "kfold",
      "k_folds": 5,
      "n_repetitions": 3, # new
      "shuffle": True,
      "stratify": True,
      "random_seed": 123
  }
  ```