Redirect the sandbox landing page to a page of our docs.

[iAmMichaelConnor]

I think we should get rid of the sandbox landing page (in its current form - i.e. get rid of the separate sandbox-website repo) for the public release, and instead redirect [the sandbox landing URL] to the same information, but as a page in our docusaurus docs.

Reasons:

• Having this one page live in a separate repo is a pain. It's not covered by our docs CI, and so we keep breaking the commands and having to do manual updates. It's not sustainable and gives bad first impressions.
• The appearance of the page isn't great, whereas the docs layout looks clean and polished.
• The code snippet boxes aren't formatted nicely and have already taken up more time than they deserve, whereas docusaurus just works.

[catmcgee]

https://aztec-docs-dev.netlify.app/dev_docs/getting_started/quickstart

[spypsy]

This is now live, redirecting to https://docs.aztec.network/dev_docs/getting_started/sandbox