[Subtask] Connectors for Flink SQL Query Engine -> Flink Table Store

[a49a]

Code of Conduct

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

Search before asking

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

Describe the subtask

Add a doc of Flink SQL Query Engine for Flink Table Store

Parent issue

https://github.com/apache/incubator-kyuubi/issues/3059

Are you willing to submit PR?

• [X] Yes I am willing to submit a PR!

[a49a]

I would like to take this.