Add the option for keyboard navigation with Virtualizer

[michael-lauridsen]

Is your feature request related to a problem? Please describe.
I have the issue that keyboard navigation does not work properly with the Virtualizer component for items not being rendered. This causes an issue with accessibility when trying to enable keyboard navigation in a long list.
The issue can be reproduced in the official demo: Radix Select with Virtualizer - For example if you open the select and press B you will only cycle through the shown items, but never the ones further down in the list. I would expect it to navigate through the whole list before it loops.

Describe the solution you'd like
Option to reactively set the index or a scrollTo function.

Describe alternatives you've considered
I have tried to handle finding the index of the child item that starts with the key pressed, but I ended being stuck as I could not find a way afterwards to control the list.

Additional context

[inokawa]

Option to reactively set the index or a scrollTo function.

Could you explain it in detail?