Prefetch JSON support for faster amp-list rendering

### Description

With this feature we are hoping to achieve support for Prefetching on the amp-list component. This would give developers the ability to Prefetch data which would result in quicker rendering.

### Alternatives Considered

Possibly enabling the component to prefetch and store the data in local storage then rendering from there. Currently looking into this and will update this thread when a more refined idea comes along!

### Additional Context

_No response_

The issue does not name files, tests, or an entry point. Start by locating the amp-list component's data-fetching and rendering code, then determine how prefetching should be defined and whether storage is required. Done means an agreed design and tests demonstrating prefetched data enables faster amp-list rendering.

Written by the indexing model from the issue text.