[FEA] Provide cuML wrapper of RAFT DeviceResourcesSNMG

At least two estimators (UMAP, HDBSCAN) now support SNMG ANN graph construction via a `DeviceResourcesSNMG` handle.

Using this requires knowledge of RAFT, which feels unnecessary. A cuML Python user shouldn't need to understand or be aware of RAFT to fully utilize a single machine for algorithms that support it via entirely C++-based mechanisms.



