Add tutorial in docs about how to use benchmarks

[fusawa-yugo]

Motivation

Guides on benchmarks in OptunaHub would be useful for users.

Description of the changes

I added use cases for normal problem, constrained problem, and multi-objective problem.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.37%. Comparing base (ff4ea79) to head (0dac627).
⚠️ Report is 13 commits behind head on main.

Additional details and impacted files

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  Coverage   81.37%   81.37%           
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  Hits          166      166           
  Misses         38       38           

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[y0z]

I leave some comments.

[y0z]

Suggested change

	In this tutorial, we will explain how to use benchmarks in optunahub.
	In this tutorial, we will explain how to use benchmarks in OptunaHub.

[y0z]

Please add some explanation of what OptunaHub Benchmarks is.
It is also helpful to add links to the Medium article (https://medium.com/optuna/optunahub-benchmarks-a-new-feature-to-use-register-various-benchmark-problems-694401524ce0) and how to implement original benchmarks (https://optuna.github.io/optunahub/generated/recipes/006_benchmarks_basic.html, https://optuna.github.io/optunahub/generated/recipes/007_benchmarks_advanced.html).

[y0z]

Please add an example to use OptunaHub Benchmarks with optimizers other than Optuna, like https://medium.com/optuna/optunahub-benchmarks-a-new-feature-to-use-register-various-benchmark-problems-694401524ce0.

[y0z]

The doc of the evaluate method is here.

[y0z]

Please add an explanation of evaluate_constraints, which allows constrained optimization with optimizers other than Optuna by directly evaluating constraints with user-provided parameters.

[y0z]

LGTM