Secure and speedy builds

[ruffsl]

Looks like we are still using wget to fetch the gpg key 97ccc7e. Using a check sum is much better than before, but this still requires two apt-get update calls for every build to install the wget prerequisite. I've suggested using gpg's key server function along with a high-availibility subset of a public keyserver pool in ruffsl@2000a09 to circumvent this issue like in docker's docs, but no takers thus far. This is Nvidia's key correct? Is Nvida planning on running an independent key server?

[3XX0]

Thanks for your input, the wget prerequisite has been removed.

[ruffsl]

Nice, creative solution. 👍
I spent some time looking at gpg for a similar feature,
this should help build times.