DOC: Add open source diagram tooling

[VeckoTheGecko]

I think our documentation can benefit from having diagrams to help explain certain concepts. There's the general setup of Parcels, which already has a diagram, but other concepts which might benefit are:

• The concept of chunking (which is important when it comes to working with xarray)
• The concept of SGRID
• (potentially) some stuff on the unstructured grid side

With these diagrams, however, they should be easy to edit with open source tooling. That is a major consideration, as it means that they can be easily editted down the line.

Stylistically I'm a huge fan of excalidraw, but that may be too simple (i.e., have the flexibility that we would need, it only allows for simpler shapes).

Another option is draw.io - which was used to create the original diagram of the layout of parcels (I like this a bit less)

What do you think @erikvansebille ? (if you're keen for diagraming tooling - perhaps have a play with those linked above, or see if there are other open source diagraming tools that you like)

When it comes to integrating these into the documentation, I have the following in mind:

(using excalidraw as an example)

• Store the source files (e.g.,) sgrid.excalidraw in a docs/assets/excalidraw folder
• Use a Pixi task to automatically build these into PDF files (this is automatically run during the docs process)
• Use the PDF outputs and embed into website

[erikvansebille]

Thanks for raising this, @VeckoTheGecko. Yes, diagrams are a good idea; also for a potential paper on the new v4 code.

I fully agree that diagrams should be created with open source tools and easily adaptable. Reint used draw.io before, but that's rather complex. I do like the style of the diagrams you make with excalidraw, so that seems indeed like a good tool to start using. So go ahead with that, if you want!

[VeckoTheGecko]

This would support a very wide range of diagrams. I'll work on this