With the recent announcement of a [Vercel Microfrontends ](https://vercel.com/changelog/vercel-microfrontends-is-now-in-limited-beta) what's the difference between this and using Zones that have existed for some time? I can't quite figure out what the announcement is and how it differs. Is this just a change in Vercel infra to allow easy hosting of such architectures? If so is it possible to self host this?