Add Notebooks For All usability test results

[isabela-pf]

I'm excited to bring some accessibility efforts to the Jupyter surveys repo!

This PR:

• Creates a directory under surveys for the Notebooks For All project (accessibility testing and fixes for HTML converted notebook files and nbconvert)
• Adds a project readme that provides information about the tests. It also links to the results and resources.
• Adds the project to the root repo readme under Jupyter user surveys

Please let me know if you have any questions. Thanks in advance for review! 🌻

cc: @eteq, @Jenneh, @smythp, and @tonyfast because your names are mentioned as the project team.

[isabela-pf]

I know this repository is low traffic, but I want to make some noise to ping this for review again if possible. Please let me know if there's anything I can do to make review easier. Thank you! 🌻

[tonyfast]

i've looked through and im super excited to see these results be upstreamed. i can't merge, but i'll sign off on a review.

[tonyfast]

@Carreau @Zsailer any chance yall could merge this?

[Zsailer]

Thanks, @isabela-pf! This looks awesome. Great work!

Unfortunately, I don't have merge rights on this repo anymore. I think I did at one point, but I was probably dropped when we refactored the governance structure.

[Carreau]

Boom, merged.

[isabela-pf]

Thank you!