Landing Page UI update

[dmarvp]

Summary

We want the docs landing page to be friendlier and better looking too. Ideally, it should have a small text accompanied by a graphic (we can use the same graphics we already have on the web) for:

• CLI and Proxy
• Unit Testing
• End to End Testing
• Continuous Testing
• Usability Testing

Some doc pages to use as inspiration:

https://www.algolia.com/doc/
https://pusher.com/docs
https://www.jovo.tech/docs/
https://messente.com/documentation
https://stripe.com/docs