[Feature][python] Add sphinx ext to get part of code from example

### Search before asking

- [X] I had searched in the [issues](https://github.com/apache/dolphinscheduler/issues?q=is%3Aissue) and found no similar feature requirement.

### Description

To avoid duplicate code of the document, we should create a sphinx extension and quote code from the document. About extension for sphinx you could find in https://www.sphinx-doc.org/en/master/development/index.html.

### Use case

_No response_

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

Start with the Sphinx extension development documentation linked in the issue and inspect the repository's documentation and examples to identify where duplicate code is currently maintained. Done means a Sphinx extension can quote part of code from an example so the documentation no longer needs duplicate code.

Written by the indexing model from the issue text.