Rework how the nvidia-container-toolkit vends subpackages

**What I'd like:**
Currently, the `nvidia-container-toolkit` package provides, among other things, the `nvidia-container-runtime-hook` and `nvidia-ctk`. There are downstream builders that don't want/need `nvidia-container-runtime-hook` but still need `nvidia-ctk`. Since Bottlerocket NVIDIA variants still need the legacy `nvidia-container-runtime-hook`, it can't be deprecated and removed from the package thus we should vend `nvidia-ctk` as a subpackage of `nvidia-container-toolkit` so that downstreams get only what they need without breaking existing variants.

**Any alternatives you've considered:**
Vend both as they are today, even if downstreams don't need `nvidia-container-runtime-hook`.