Particle BCs without relocatable device code

[brryan]

PR Summary

Particles currently use relocatable device code via inheritance to provide boundary condition functions on a per-particle basis. This PR moves to boundary conditions on particles via kernel launches in a manner analogous to field boundary conditions.

Breaking: completely new particle BCs for downstream codes doing custom implementations.

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
• Merge Forest Of Octrees #1009
• Fix particle tracers bug (missing dependence for Defrag task)
• Add particle_tracers example to CI

[lroberts36]

@brryan: ok, that makes sense. I was just going to try and start seeing what is required to merge this with the mesh constructor refactor PR and the forest PR that is currently in WIP.

[pgrete]

As for the SwarmPacks I'm happy with the discussion and don't plan a detailed review. So just go ahead an merge when everyone is happy.

[brryan]

I verified that this works downstream, including custom reflecting BCs for particles, so I'm enabling auto-merge now. Thanks everyone for reviews