Unable to specify an alternative mirror for nvidia-docker and nvidia cuda drivers

[Dmitrii Shcherbakov]

nvidia_url is hardcoded to nvidia_url. For environments with restrictive proxy servers (cannot download things from github) or without public internet access at all it is necessary to be able to specify an alternative mirror and its GPG key.

nvidia_url = 'https://nvidia.github.io'

The proposal is to use layer-apt-like syntax (install_sources and install_keys) or the following:

install_nvidia_sources
install_nvidia_keys

This is needed as there are 3 repositories:

cat /etc/apt/sources.list.d/nvidia-docker.list
deb https://nvidia.github.io/libnvidia-container/ubuntu18.04/$(ARCH) /
deb https://nvidia.github.io/nvidia-container-runtime/ubuntu18.04/$(ARCH) /
deb https://nvidia.github.io/nvidia-docker/ubuntu18.04/$(ARCH) /

The code should then ignore upstream repositories if mirrors are specified.

The same applies to cuda drivers:

https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/