Adding secondary chapter navigation on left side like just-the-docs jekyll theme

### Have you checked that your feature request isn't already filed?

- [X] I read through [FAQ](https://github.com/alshedivat/al-folio/blob/master/FAQ.md) and searched through the [past issues](https://github.com/alshedivat/al-folio/issues), none of which addressed my feature request.
- [X] Yes, I have checked that this feature request isn't already filed.

### Description & Motivation

This will be particularly helpful for making complete chapter-based notes, and exercises, for the specific book. So, If I want to open notes for specific books, I will have chapter navigation on the left sidebar and the table of contents on the right sidebar.


### Pitch

_No response_

### Alternatives

_No response_

### Additional context

_No response_