Add per-library tutorial links to tutorial page

[mabelzhang]

🎉 New feature

Part of https://github.com/gazebo-web/gazebosim-web-frontend/issues/19

Summary

Add per-library tutorials directly to tutorial page.

The links are quite manual. The numbers would have to be changed each time we do version bumps. I don't know if it can be automated. We manually change numbers in other Markdown files, so maybe this is the way to go?

Test it

Use docker_dev branch in gazebosim-web-frontend repo and follow steps here https://github.com/gazebo-web/gazebosim-web-frontend/tree/docker_dev#docker-development

(Of course, I say that, but I'm not able to get the docker-compose to work. Maybe someone who has it working @azeey can preview it.)

Checklist

• [ ] Signed all commits for DCO
• [ ] Added tests
• [ ] Added example and/or tutorial
• [ ] Updated documentation (as needed)
• [ ] Updated migration guide (as needed)
• [ ] Consider updating Python bindings (if the library has them)
• [ ] codecheck passed (See contributing)
• [ ] All tests passed (See test coverage)
• [ ] While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.