text: Title: Add visualization for Optuna optimization results
  Body: In #332 we added support for Optuna. It can be used for tuning:
  - Extra Trees
  - Random Forest
  - Xgboost
  - LightGBM
  - CatBoost
  
  It will be nice to have a visualization of Optuna optimization. Optuna study results are saved as joblib in `optuna` dir.