Add a visualization package for CMA-ES

[c-bata]

Motivation

The below animation helps understanding of how CMA-ES works.

https://github.com/CyberAgentAILab/cmaes

Description

Optuna's CmaEsSampler, which uses CyberAgentAILab/cmaes under the hood, stores cmaes.CMA object in trial.system_attrs.
https://github.com/optuna/optuna/blob/62d6c6bda32e17d5b634e828855523dc06da6e84/optuna/samplers/_cmaes.py#L479-L483

Therefore, it is possible to adapt the following script into an Optuna visualization function. https://github.com/CyberAgentAILab/cmaes/blob/main/tools/cmaes_visualizer.py

Alternatives (optional)

No response

Additional context (optional)

• Please note that cmaes-visualizer.py only supports 2-dimensional search space.
• Please note that CyberAgentAILab/cmaes is licensed under the MIT. So the copyright notice should be included in the PR.
  • https://github.com/CyberAgentAILab/cmaes/blob/main/LICENSE