Add example: high cardinality case

[tsuruda-yoshito]

Add a tutorial on high cardinality cases as an example

• Create example/regression/high_cardinality_case_regression.ipynb
  • Include an explanation of high cardinality, discussing how Cyclic boosting is strong against high cardinality data and the reasons for this, along with an example of a high cardinality case.
  • Conduct regression using three datasets with varying degrees of high cardinality and compare with LightGBM (LightGBM installation required).
  • The results should show that across all datasets, LightGBM is outperformed in terms of MAE and SMAPE, with the performance gap increasing as the degree of high cardinality becomes stronger.
• Add three datasets with varying degrees of high cardinality under tests/high_cardinality_data/
  • Daily sales datasets simulated using demand forecasting simulation.