[ENHANCEMENT]: Switch to cuda::memory_resource once it is available

[sleeepyjack]

Is your feature request related to a problem? Please describe.

We currently roll our own default cuco::cuda_allocator, which internally calls cudaMalloc/cudaFree. This approach doesn't leverage the concept of stream-ordered allocations, which might degrade performance for operations such as size() and insert(), where we allocate intermediate storage to retrieve the count.

Describe the solution you'd like

libcu++ v2.0 introduces a new cuda::memory_resource (design, initial PR, final PR).

We should use this facility instead.

Describe alternatives you've considered

No response

Additional context

No response

[sleeepyjack]

Will be available once rapidsai/rapids-cmake#399 is resolved