AMP story Player: optionally setting the first story to pre-render state

## Describe the new feature or change to an existing feature you'd like to see
- Currently the amp player loads the first story in visible state then pre-render the rest.
- If would be in handy if there was an option to also set the first story to be in pre-rendered state to improve the performance of the render in cases where the first story doesn't need to be in visible state first.

## Describe alternatives you've considered
- Loading the story on user action. This will now set the first story to visible and pre-render the rest.

cc @Enriqe