Change the build + deploy the website to use the registrygen tool

[stack72]

We move the checkout of the registry to the GHA and we then run the registrygen generate all-docs command and pass the path to the registry packages folder

This will generate all package docs + API Navs

Proposed changes

Unreleased product version (optional)

Related issues (optional)

[stack72]

Thisnis expected to fail until the associated registrygen cli command is available when the PR upstream is merged

[cnunciato]

@stack72 Do y'all want to take this issue from here, or want me to? I'm happy to pick it up if you like. Is there anything blocking it at this point?