Add GPU support for CAGRA

[nwstephens]

Milvus Lite does not support CAGRA and several other NVDIA cuVS features. It only supports flat methods. The Retriever team would like support for CAGRA in order to develop AI workflows.

@randerzander

[junjiejiangjjj]

hi @nwstephens , milvus-lite currently has no plans to support GPU. If you want to use GPU, you can use milvus

[nwstephens]

@junjiejiangjjj I discussed GPU support with @liliu-z previously. He said that supporting GPUs would be a major change, but I don't recall him saying that it was off the table. I hope that GPU support will be on the roadmap for Milvus Lite. I created this issue to track it over time.