Remove Legacy CUDA and disable QMC_CUDA build option

[ye-luo]

Proposed changes

A good day. I have not touched tests folder, need to decide how to clean up/repurpose if there is any need.

What type(s) of changes does this code introduce?

• Other (please describe):

Does this introduce a breaking change?

• Yes, legacy CUDA is gone

What systems has this change been tested on?

epyc-server

Checklist

• Yes. This PR is up to date with current the current state of 'develop'

[ye-luo]

Test this please

[ye-luo]

Test this please

[ye-luo]

Test this please

[prckent]

Depending on available energy there are additional files and directories to cleanup or decide to tackle in a later PR:

• README.md
• docs/*.rst
• config/*.sh
• CMake/*.cmake

I changed the title to be more obvious to non-specialists.

[prckent]

I have updated the branch protection rules so that results from legacy CUDA builds are not required to pass.

[prckent]

Note that I don't know what, say, "ornl-nitrogen CI GCC9-MPI-CUDA-AFQMC-Complex " actually is. It passes so it can't be using legacy CUDA and it is also definitely not an offload build if it is using GCC9. The name needs updating. (@williamfgc ?)

[ye-luo]

Note that I don't know what, say, "ornl-nitrogen CI GCC9-MPI-CUDA-AFQMC-Complex " actually is. It passes so it can't be using legacy CUDA and it is also definitely not an offload build if it is using GCC9. The name needs updating. (@williamfgc ?)

This is ENABLE_CUDA+BUILD_AFQMC without offload.

[ye-luo]

Depending on available energy there are additional files and directories to cleanup or decide to tackle in a later PR:

* README.md

* docs/*.rst

* config/*.sh

* CMake/*.cmake

Added #4432

[williamfgc]

Yes, Legacy-CUDA jobs are marked explicitly anticipating this PR. After this gets merged I will reorganize CI scripts to separate ornl from GitHub Actions runners workflows.

[prckent]

Thanks Ye for this 40K source line removal!

I'll note that this PR is fully consistent with the advertised planned removal of the limited feature legacy CUDA support in the 3.16.0 release notes. Users needing NVIDIA GPU support should switch to the offload build with CUDA optimizations, i.e. ENABLE_OFFLOAD=ON, ENABLE_CUDA=ON. This version and the associated batched drivers support more features and is already being used for production science.