Added nesting of sidebar items

[Om-Doiphode]

Fixes issue #713

• Changed the documentation theme from furo to pydata-sphinx-theme
• Implemented nesting of menus and submenus in the Section Navigation.
• Improved the overall structure and navigation of the documentation.
• Ensured that all relevant sections are properly organized under their respective categories.

[henrykironde]

@Om-Doiphode, thank you for these changes. The documentation updates align well with what we discussed. However, I have a few suggestions:

It's standard practice to keep the source or api directories dedicated solely to API module documentation. This helps streamline maintenance when the source code is updated. The conf.py file should remain in the default location: docs/conf.py. I don't think we need the deepforest_docs folder. We can remove it, and all the subdirectories can be moved directly under docs/.

We still have some redundant parts like getting started appear twice, in the introduction and again as a main topic.

[henrykironde]

Can you rebase with main

[henrykironde]

Make this one commit. Amend the commits to one

[bw4sz]

@Om-Doiphode Once you rebase, i'm excited to get this merged. Let us know if you need help.

[henrykironde]

Make one commit.
Make sure the tests pass. Look at the error message and see if you can figure out the reason why it is failing.

[henrykironde]

remove this dep, "docutils<0.18"

[henrykironde]

@Om-Doiphode Use pytest --nbmake docs/**/*_test.ipynb to test specific notebooks. To exclude certain notebooks from CI/CD runs, ensure the ones you want to test end with _test.ipynb. This approach avoids running time-consuming notebooks that should be tested locally. Make sure when you run ls docs/**/*_test.ipynb locally, you retriever the files expected to be tested.

[bw4sz]

@Om-Doiphode, rebase, there was another PR.