Support RBE where worker image has no cuda install

[jsharpe]

It'd be good to support a completely hermetic toolchain so that RBE can be used without needing a special image for workers.

[hofbi]

Did anyone made some progress on this? Maybe fetching the cuda toolkit as a tarball and pass it to the rules_cuda toolchain?

[jsharpe]

#72 - is an initial stab at this - I'm using this at work for our CUDA use case and its working ok for us but its not in a state yet that it can be merged into the upstream repo. Feel free to pick up breaking down this into changes that can be landed if you have bandwidth to.

[udaya2899]

Thanks for the starting point @jsharpe, would it be possible to merge this PR, or do you know if there are specific points that need to be addressed in the PR?

[jsharpe]

Unfortunately that PR breaks the local cuda toolchain so it can't be merged as is. It needs breaking down into smaller PRs really and merged step by step.