Add example for using multi-sheet Excel file

[ankatiyar]

Description

Resolves #1700

Development notes

Checklist

• [ ] Read the contributing guidelines
• [ ] Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• [ ] Updated the documentation to reflect the code changes
• [ ] Added a description of this change in the RELEASE.md file
• [ ] Added tests to cover my changes

[datajoely]

Can I ask that we include the example how to save a multi-sheet as well? The instructions to do so are buried in in the DataSet docstring: https://github.com/kedro-org/kedro/blob/59064403e2590c992dceb51942f7dd9f6c97898a/kedro/extras/datasets/pandas/excel_dataset.py#L104

[merelcht]

Side notes: Follow up on previous discussion about DataSet API Docs should be the 1st entry point for people looking up examples, I think we should do the followings:

1. Remove these number, i.e. Example X, make them a sub-header like ## Save-an-image-xxxxx, so we can link these example directly in the doc, and also better SEO I think?
2. Only keep some of the example in Data Catalog to showcase what Kedro can do, but leave the advance example in the Corresponding API Doc.

Yes we should, but let's do that as separate tasks to keep this PR focussed on one thing. We've got this issue for task 1: https://github.com/kedro-org/kedro/issues/1742. I'll update it so it covers point 2 as well.