Return also the keypoint scores

[kmyi]

We are currently not returning the keypoint scores, which can be annoying when including it to other benchmarks. Can we also return them? I've seen in

lf-net-release/inference.py

Line 203 in 53c579c

kpts_ori = batch_gather_keypoints(ori_maps, batch_inds, kpts)

That we might want to also get them here.