text: Title: provide a way to use hyperparameter-tuning
  Body: 
  ### Description
  
  It would be great to provide a way to use hyperparameter-tuning in igel. The user should be able to write that he wants to use hyperparameter-tuning in the yaml file and this will be automatically triggered by igel before fitting a model.
  
  This can be achieved using grid search or maybe random search. Sklearn already have APIs for this. It just needs to be implemented. 
  