[Intro page] Design and user experience

[rianrietveld]

URL: https://wpaccessibility.org/docs/topics/design/
Code: https://github.com/wpaccessibility/wp-a11y-docs/blob/main/docs/topics/design/index.md

Please read How to contribute before you start.

Tasks

• the intro text needs to be rewritten
• the resources needs to be moved to the related topics.