[4/n][torch/elastic][upstream] Move torchelastic/metrics to torch/distributed/elastic/metrics (#53870)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/53870
Move torchelastic/metrics to torch/distributed/elastic/metrics
Test Plan: buck test mode/dev-nosan //pytorch/elastic/torchelastic/...
Reviewed By: kiukchung
Differential Revision: D26970901
fbshipit-source-id: 0e0a211fe509b7bc3ab10adfefba81cd71b6db37