Add Examples showing the use of BoTorch

## Motivation

This issue is meant to be a tracking issue to add examples that showcase the integration of optuna with BoTorch, pycma and SHAP. I've chosen not to add [Apache MXNet](https://github.com/apache/mxnet) as the project is now read-only.

## Description

Create examples that showcase the integration of optuna with BoTorch, pycma and SHAP.


