Audit packages disabled in CI and enable all the ones we can

[LegNeato]

CI excludes packages here from building:

Rust-CUDA/.github/workflows/rust.yml

Line 104 in 2b33f4e

run: cargo build --workspace --exclude "optix" --exclude "path_tracer" --exclude "denoiser" --exclude "add" --exclude "ex*"

Without having these tested in CI, we will not be aware if they regress / stop building.

We should figure out why these are disabled and possibly create custom jobs for them if required.

[LegNeato]

The excludes were added in #1

[jorge-ortega]

With #188, I think we should be able to build add and even test it when we land #184.
The rest have to do with Optix, which we still don't have a solution for in our CI yet. I'm looking back to our discussion in #142. We'll need one if we want to remain its stewards.

[adamcavendish]

The OptiX ones I think the major issue is OptiX SDK installation which users will have to accept a licence and there is no public download URL without login.

[jorge-ortega]

Seems then the best anyone ever could do is build and test locally. Then these would just stay disable indefinitely.