improve dependencies on the nvidia driver

This could solve https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=948952 It allows users to run primus-vk with the nvidia tesla driver, by installing primus-vk-nvidia libnvidia-tesla-glvkspirv nvidia-tesla-driver-libs nvidia-tesla-kernel-dkms or just making sure that the glx-alternative selects the tesla-driver and the tesla driver is installed. I think the restructuring and depending on more higher-level packages improves the dependencies overall.