[Improvement] Supply more demo datasets for playground

Code of Conduct

• I agree to follow this project's Code of Conduct

Search before asking

• I have searched in the issues and found no similar issues.

What would you like to be improved?

I find some public small datasets

• https://kylin.apache.org/docs31/howto/sample_dataset.html
• https://www.briandunning.com/sample-data/

Other datasets are welcome, especially could be used to draw charts by BI tools.

How should we improve?

No response

Are you willing to submit PR?

• Yes. I can submit a PR independently to improve.
• Yes. I would be willing to submit a PR with guidance from the Kyuubi community to improve.
• No. I cannot submit a PR at this time.