[FEA][JNI] Move to RMM apis get_current_device_resource_ref and set_current_device_resource_ref

[abellina]

This change rapidsai/rmm#1661 deprecates the pointer based get_current_device_resource and set_current_device_resource in favor of a non-owning reference based set_current_device_resource_ref and get_current_device_resource_ref.

RMM JNI currently uses the pointer based apis so we want to move to the new _ref versions. I don't think we need to worry about ownership, because we already have a java object tracking a heap allocated memory resource.

[harrism]

Thanks for the issue. #1661 does not deprecate anything yet. I'm still experimenting with minimizing how invasive the changes have to be.