Docs request: Centralized documentation for available results

### What is the documentation improvement or update you wish to see?

Currently, I don't think we have centralized docs where OpenScPCA contributors (and others!) can learn about the available results. We have documentation _that_ results are available and how to obtain that, but the specific information about which modules have available results and what their contents are are quite spread out.

I am therefore opening this issue to suggest we add some information about available results. I think this could be a good way to go about it:
- Add a table to the `analyses/README.md` file listing mature modules which have available results. This table can link to the module itself as well as the `OpenScPCA-nf` module. Might be helpful to also link to any Discussion that introduced those results when they were first released.
- On the website in both the `download-results.py` sections and the `OpenScPCA-nf` sections, add statements that the repo's `analyses/README.md` file has a table of available results

### Is there any additional context you would like to provide?

N/A

### If this request is for an existing documentation page, please provide the link here.

Existing docs pages where we should say you can find available results in the README:

- https://github.com/AlexsLemonade/OpenScPCA-analysis/blob/d3be004794fe1d011c8ea191171dc89d21d8fd7a/docs/ensuring-repro/openscpca-nf/index.md
- https://github.com/AlexsLemonade/OpenScPCA-analysis/blob/d3be004794fe1d011c8ea191171dc89d21d8fd7a/docs/getting-started/accessing-resources/getting-access-to-data.md

Start by reviewing analyses/README.md and the two linked documentation pages: docs/ensuring-repro/openscpca-nf/index.md and docs/getting-started/accessing-resources/getting-access-to-data.md. Identify the mature modules with available results, document them in a README table with the requested links, and add guidance on the website pages pointing contributors to that table.

Written by the indexing model from the issue text.