Docs lena

[lenajlassi]

Hi Thomas,

I made some big changes to the documentation (mostly structural):

• I reorganized the notebooks so that it is clearer and better structured. For example, I merged the various notebooks that created and loaded data into one file, as I found this confusing when learning how to do radial profiles with paicos. Now, one learns how to use the projector/slicer/histogram(2d), save it, load it and plot it all in the same notebook.

• I added a short clarification on the available projectors in creating_slices_projections.ipynb because I felt it was missing. I wanted to include an example of the TreeProjector, but it was so long that I decided to exclude it and point to an examples/ script instead, and wrote a "NOTE: [...]" to explain that this takes longer

• I modified the numbering of the notebook-tutorials and checked the general structure of all of them. Unfortunately, I could not run the example_gpu_sph_projector.ipynb and lost the output of the cells. Could you run them again and push those changes? I tried restoring the file but couldn't get the output back.

• I made all these changes in notebook-tutorials and then copied over the same changes to docs/source/ as needed. It's a bit weird to have to do this, so let me know if there is a better way.

• I am confused about the different uses of NestedProjector and Projector? I've always used Projector itself, and I guess NestedProjector is more recent. It's not clear to me which one should be used and what for? I therefore left the Projector class in the notebook tutorial, but I will change this if we want users to prioritize using NestedProjector.

I think that is mostly it. Unfortunately I did not know how to check my changes directly in the documentation page itself, so I cannot be sure that it will look as intended.

All these changes were made based on my experience learning how to use Paicos, and my perspective on what's important for beginners. I thought that if the very basics of learning to use Paicos are confusing, it will deter people from using this code. And we don't want that :D

Léna

[tberlok]

Thanks for carefully going through this Léna! Overall these seem like very good suggestions. The diffs do not work well on notebooks, so I will merge and then have a more detailed look.