Documentation update

[ThijsVroegh]

Summary: This PR updates the project documentation of Unraphael to reflect recent changes in the streamlit pages. Key updates include:

• [x] Updated the structure
• [x] Added contents for most pages, including background, overview, and description of all the streamlit pages
• [x] These updates will improve the comprehensibility and usability of the documentation, ensuring that users have accurate and up-to-date information. It also gives further structure for ourselves

[ThijsVroegh]

@stefsmeets Many thanks for all the suggestions! Yep, got into a writing mode 😅 . I included all your tips, and now the structure is hopefullly less overwhelming haha!

[stefsmeets]

I don't know @ThijsVroegh , I don't think this structure is all that great. It's a lot of text and I'm not sure what it is documenting. It does not link to any of the pages that we have in the application, and if I want help on any of the pages, where do I go?

Crucially, it is missing installation and usage instructions. We have these front and center in the current version of the docs: https://unraphael.readthedocs.io/en/latest/

I think this is a step backwards.

[stefsmeets]

I revised the documentation addressing some of my own comments. I also flattened the layout to make it a bit easier to navigate, and removed some of the superfluous pages.

https://unraphael.readthedocs.io/en/documentation/

I'm going to merge it now, let's pick up remaining issues in a new PR.