Provide clearer documentation around NVIDIA's timeslicing configuration

Even though the website provides documentation for TimeSlicing and other NVIDIA capabilities, customers have a hard time connecting the dots (e.g. should they still use `NVIDIA_VISIBLE_DEVICES` along with TimeSlicing? should they use `cdi-cri` over `envvar` when using TimeSlicing, should they even have to worry about `NVIDIA_VISIBLE_DEVICES`).

These sort of questions could be added here in the website or in a Bottlerocket discussion.

Review the website's existing TimeSlicing and NVIDIA capability documentation first, then compare it with the questions listed in the issue. Done means clearly documenting whether NVIDIA_VISIBLE_DEVICES is needed, whether cdi-cri or envvar should be used, and where this guidance belongs, either on the website or in a Bottlerocket discussion.

Written by the indexing model from the issue text.