Consider renaming memory resources we provide in cudax #6177
Description
As a follow-up to #6097 we now have an owning and non-owning memory resource types. It might be better to rename them to memory_pool and memory_pool_ref to provide a name that is more familiar to someone coming from the old CUDA Runtime. In general only more advanced users should care what a memory resource is and that they can use something beyond just the default resources.
There was also a request to name the managed_* part differently here: #4094
We could also consider naming the pinned_* differently, because technically device memory is also pinned, maybe host_* would be a better choice