Conversion to new ETI requiring minimal C++ code additions

[jjwilke]

No description provided.

[jjwilke]

Work in progress. PR open if anyone wants to review the initial implementation and give feedback before renovating the entire repository.

[mhoemmen]

It's great to get rid of the files we don't need that nevertheless occupy build time :-) . Will the next step be removing redundant instantiations (e.g., Cuda, AnonymousSpace replacing the double instantiations for CudaUVMSpace and CudaSpace)?

[jjwilke]

@mhoemmen I think changing to AnonymousSpace is above my pay grade. My understanding is that CudaSpace is "zero-overhead" convertible to AnonymousSpace, so this probably makes sense to do? I'm not familiar enough with the code base to know how much algorithm specialization based on the memory space? I know we do specialization based on the execution space. @kyungjoo-kim @srajama1

[mhoemmen]

@jjwilke We've talked about this before; I just want people to keep it in mind that kokkos-kernels likely has redundant instantiations that consume build time and space. Functions that don't allocate Views really don't need to have multiple instantiations for different memory spaces but the same execution space.

[jjwilke]

Too many changes including file renames for this PR to remain useful. Canceled in favor of PR #526. Cherry-picked commits into new PR.