Update to gcc 12

[alexbaden]

No description provided.

[alexbaden]

This is now ready for review.

@leshikus I made some small changes to CI to work with gcc-12. The biggest change is to using apt for cuda, instead of conda. I was also able to reduce the installed packages to just nvcc and its dependencies, excluding most of the cuda toolkit. That dropped install size and install time. This also allows us to use cuda 12 in CI, our preferred cuda version.

@kurapov-peter @ienkovich gcc-12 has worked fine for me in conda dev so far. Let me know if you see any issues in your envs.

[ienkovich]

I got the clean build locally with this branch. Thanks!