Add README for documentation

[SuperCowProducts]

I'm pleased to say this project's documentation builds flawlessly first-try AND has is capable of generating a beautiful PDF - a very rare case indeed!

I put the steps I followed down in a README.md inside the `doc' folder - you'd probably want to adapt it, but I though it was worth 1. noting down the precise procedure I followed for future reproducibility, 2. letting users expllicitly know building the docs is an ordinary and supported procedure - perhaps we can add a pipeline to auto-build PDF on Read the Docs?

Thank you for this project, I'm excited to try seamless graph creation from SymPy calculations

[SuperCowProducts]

I've also generated a table of contents ready to be embedded inside the PDF, and have also provided the original recipe.toml file for the very first automated heading-detection step.

[Davide-sd]

@SuperCowProducts thanks for the effort. I looked at the PDF file and it looks like you used the minimum install option, as only charts generated by Matplotlib where included.

On my development environment, with all the dependencies installed, I run the exact command: it mostly worked, in the sense that almost all of the plots (generated with Matplotlib, Plotly, K3D-Jupyter) were included. However, there were a couple of issues, namely with GIFs that can't be included in a PDF, and with some unicode characters being problematic in Latex.

At the moment, I don't have time to work out these issues, so I'll leave this PR open. Feel free to give it a try...

[SuperCowProducts]

@SuperCowProducts thanks for the effort. I looked at the PDF file and it looks like you used the minimum install option, as only charts generated by Matplotlib where included.

On my development environment, with all the dependencies installed, I run the exact command: it mostly worked, in the sense that almost all of the plots (generated with Matplotlib, Plotly, K3D-Jupyter) were included. However, there were a couple of issues, namely with GIFs that can't be included in a PDF, and with some unicode characters being problematic in Latex.

At the moment, I don't have time to work out these issues, so I'll leave this PR open. Feel free to give it a try...

Thank you for the clarification, I usually skim through those errors as I find it surprising if the PDF is actually generated at all lol. I'd need to check if LaTeX has GIF support at all, and as for Unicode, usually that's a sign some extra packages are needed in the preamble. Then it should be fine.