Kokkos Tools first attempt

[DavidPoliakoff]

Summary

• This PR is a feature
• It does the following (modify list as needed):
  • Adds partial support for Kokkos Tools to RAJA

Design review (for API changes or additions---delete if unneeded)

We have not yet done a design review.

I wanted to get this started before taking off. In Kokkos, we've managed to isolate the vast majority of the plumbing to allow Kokkos Tools to operate in other programming models, including RAJA (this PR).

What would need to be done to bring this to production would be

• Plumb however you load tools in with how we do it. If you have an environment variable you recommend people set to load a tool, populate the Kokkos::Tools::InitArguments with it (or ask people to call RAJA::initialize(argc, argv) and just use our arg-parsing) before calling Kokkos::Tools::initialize
• Possibly start using this with your named kernel facilities
• For something crazy high-impact, add autotuning. RAJA::forall<cuda_autotuning_exec>, which will by the way work with your Apollo tool if you implement it with Kokkos Tools
• Fix the build system weirdness. I put the header files in impl/ in include, because I get CMake errors if I put them in include/RAJA/tools/impl

Anyway, this is something you could work on with the Kokkos team, if it's of interest