[FEA] Make rmm host memory resource extend std::pmr::memory_resource

[nirandaperera]

Is your feature request related to a problem? Please describe.
I would like to use rmm host memory resources with std pmr pool resources, which requires a std pmr memory_resource impl.

Describe the solution you'd like
Make rmm host memory resource extend std::pmr::memory_resource

Describe alternatives you've considered
N/A

Additional context
@harrism suggested that this needs to be discussed in an issue in this PR #1960

Draft PR #1960

[bdice]

I'd vote to put this on hold until we can evaluate a migration to <cuda/memory_resource> (NVIDIA/cccl#1502). That's something we know we want to do, and it may add constraints on whether RMM can (or should) extend std::pmr::memory_resource.