Figure out how to toggle Risc0 CUDA proving

[yaziciahmet]

We want to have CUDA proving (and potentially Metal) enabled, but also don't want to break local builds on the machines that don't have support for these accelerators. We need to find a way to conditionally build the risc0.

My first guess is that we will need to benefit from the build.rs script of the guest code to discover whether the machine has support for these, and build conditionally.

[eyusufatik]

removing milestone since we cant merge cuda pr (#1380 )