[EPIC] Roadmap for cuda/memory_resource

`cuda::mr` is intended to be the future of heterogenous memory allocation in CUDA C++. It is inspired heavily by lessons learned in RMM and our experience with the `device_memory_resource*` and friends. `cuda::mr` does not seek to replace RMM, but instead distill and standardize the best parts of RMM into a more central location. Furthermore, RMM is already in the process of rebasing on top of using the `cuda::mr` interface.

### Scheduled for 3.1:
- `[synchronous_]resource` concepts
- Property system

### Scheduled for 3.2:
- [x] https://github.com/NVIDIA/cccl/issues/2128
- [x] https://github.com/NVIDIA/cccl/issues/2130
- [x] https://github.com/NVIDIA/cccl/issues/6097
- [x] https://github.com/NVIDIA/cccl/issues/2131
- [x] https://github.com/NVIDIA/cccl/issues/6009
- [x] https://github.com/NVIDIA/cccl/issues/6177
- [x] Type erased memory resource wrappers

### Future:
- [ ] https://github.com/NVIDIA/cccl/issues/2129
- [ ] https://github.com/NVIDIA/cccl/issues/2143
- [ ] https://github.com/NVIDIA/cccl/issues/2132
- [ ] https://github.com/NVIDIA/cccl/issues/2474
- [ ] https://github.com/NVIDIA/cccl/issues/2142

### Misc
- [ ] Add NVTX annotations to all memory resources
- [x] https://github.com/NVIDIA/cccl/issues/2313
- [x] https://github.com/NVIDIA/cccl/issues/2891

### Concrete types that satisfy the C++ allocator requirements
- [ ] A `cuda::mr::allocator` capable of preserving concrete type of the resource (no type-erasure)
- [ ] A `cuda::mr::polymorphic_allocator` constructible from a `resource_ref`

Questions we'll need to answer along the way:
- What lifetime semantics do we want to use for resources + allocators + data structures?
- RMM took a very relaxed approach of using non-owning references everywhere, but this is worth reconsidering (see https://github.com/rapidsai/rmm/issues/1492
- Do all data structures only take Allocators? Or just resources? Both?
- In RMM, we took an approach of only constructing from resource_refs directly, but this was mostly for expediency and convenience, so it is worth reconsidering.