Bring needed parts of aztec-sandbox repo into monorepo.

[charlielye]

The sandbox-website repo is not part of the monorepo, as at one point it had a password.
Come to think of it, the password was fully exposed in the webapp source code, so why this needed to a separate private repo im not sure!
https://github.com/AztecProtocol/sandbox-website

I also believe that we don't use the sandbox website anymore, but we still need to have the curlable script published to a bucket.

This is issue is to get rid of this repo and website, and to bring the install script into the monorepo, and ensure its deployed along with our releases.

[spypsy]

Fixed in #3617
Repo still needs closing