[WIP] Bump Kokkos5

[acreyes]

PR Summary

Bumps the kokkos version to 5.0. This didn't break much

• C++20 wanted some operator==s to be const
• ::HostMirror was deprecated in Kokkos5 in favor of ::host_mirror_type
  • this PR also makes that substitution in all the ParArrays for consistency
• g++ was a lot more strict than clang about enforcing things
  • lambdas need explicit this capture or else you get a warning
  • template constructors don't want explicit <T>

PR Checklist

• Code passes cpplint
• New features are documented.
• Adds a test for any bugs fixed. Adds tests for new features.
• Code is formatted
• Changes are summarized in CHANGELOG.md
• Change is breaking (API, behavior, ...)
  • Change is additionally added to CHANGELOG.md in the breaking section
  • PR is marked as breaking
  • Short summary API changes at the top of the PR (plus optionally with an automated update/fix script)
• CI has been triggered on Darwin for performance regression tests.
• Docs build
• (@lanl.gov employees) Update copyright on changed files

[pgrete]

Potential items to discuss/test prior to merge:

• Should we go c++20 with this? In the end it's the minimum version for Kokkos now as well
• What's the impact on performance? There was some discussion on this in the last Kokkos minor release so that some defaults (which are now enabled) were disabled in a subsequent patch release.