CHAI Submodule

[mdavis36]

Summary

• This PR is a feature:
  • It brings CHAI in as a submodule for use in the GPU port.
  • Various TPL changes were needed to get this to work:
    • Updating Axom to v0.9.0
    • cmake_minimum_version reduced to 3.14. This was required due to failing device_link stage in NVCC builds w/ the newest Axom. Probably linked to how BLT handles CUDA.
    • RAJA and Umpire added as direct dependencies.
  • Gitlab CI TPL build has been split off into its own stage. This is to reduce timeouts on CZ machines during CI runs with reasonable TPL changes.

---

ToDo :

• Annotate RELEASE_NOTES.md with notable changes.
• Create LLNLSpheral PR pointing at this branch. (PR#)
• LLNLSpheral PR has passed all tests.

[jmikeowen]

These look good to me. One question -- there are a number of changes to the PYB11Generator submodule in this pull request. Are these in a sub-branch of PYB11Generator? We may want to pull those changes to the master branch there so we can keep everything in sync and not have Spheral pointing at non-standard changes to the PYB11.

[mdavis36]

@jmikeowen Good catch on that. I need to check what those changes are, but I don't believe we need them anymore. I think they were from when I was investigating the umpire linking issue a few weeks ago.

[mdavis36]

@jmikeowen We don't NEED the PYB11Generator changes for this PR but we will need them relatively soon so we might as well bring them in here. I went ahead and made a PR LLNL/PYB11Generator#9, let's get the PYB11Generator PR in first before merging this.