Update Omega to C++20

[mwarusz]

This draft PR updates Omega C++ standard to C++20. E3SM is in the process to upgrading to Kokkos 5, which requires C++20. This PR has the necessary fixes on the Omega side.

Checklist

• Linting
  • Pre-commit run locally
• Building
  • CMake build does not produce any new warnings from changes in this PR
• Testing
  • Add a comment to the PR titled Testing with the following:
    • Which machines CTest unit tests
      have been run on and indicate that are all passing.
    • The Polaris omega_pr test suite
      has passed, using the Polaris e3sm_submodules/Omega baseline
    • Document machine(s), compiler(s), and the build path(s) used for -p for both the baseline (Polaris e3sm_submodules/Omega) and the PR build
    • Indicate "All tests passed" or document failing tests

[grnydawn]

I reviewed the code visually, and it looks good to me. All tests are passed on Frontier(craygnu-mphipcc, craycray-mphipcc, and craygnu), PM-CPU(gnu), PM-GPU(gnugpu), and Chrysalis(gnu). Approved.

[grnydawn]

Due to replacing the spdlog submodule with a new version and location, the changes to the logging module in this PR conflict with those in the develop branch.

[sbrus89]

@mwarusz, does E3SM-Project#8559 getting merged mean it is time to do another E3SM/master merge into Omega and then merge this PR?

[mwarusz]

@sbrus89

Yes, that would be good, as long as we don't run into any problems. I still need to rebase this PR. I can try to do a local merge after that to see if everything works as expected and, if there are no issues, we can go ahead with the switch. How does that sound ?

[grnydawn]

The updates in this PR are a subset of those in the previous PR. Previously, all tests passed on Frontier, PM-CPU, PM-GPU, and Chrysalis. The current PR also passed all CTests on PM-GPU and Chrysalis. Approved.

[sbrus89]

@mwarusz, will this PR fix #368, or are more changes needed in another PR?

[mwarusz]

@sbrus89

No. At first, I misread E3SM-Project#8559. That PR only changes the standard and doesn't update Kokkos. The PR we need to fix #368 is E3SM-Project#8632, which hasn't been merged into E3SM yet.

I am not sure if we want to merge this PR and do a master merge now, or do we want to wait for E3SM-Project#8632. I will leave this decision up to you.

[sbrus89]

Thanks, that's what I had suspected. Let's wait for E3SM-Project#8632 before we merge #521. Given the level of testing associated with merging master into develop, I think it makes sense to do it once rather than twice. It's good to know all the pieces are almost in place to fix #368. Thanks for helping with this!