[enhance] Replace column selectors with sklearn funcs

Currently, we are picking columns by ourselves, but since sklearn has [its own column selectors](https://inria.github.io/scikit-learn-mooc/python_scripts/03_categorical_pipeline_column_transformer.html), we can use it.

The selectors for numerical and categorical columns can be simply implemented by the following:
```python
import numpy as np
from sklearn.compose import make_column_selector as selector

numerical_col_selector = selector(dtype_include=np.number)
categorical_col_selector = selector(dtype_exclude=np.number)
```