[DataLoader] Change Decoder signature and add MatHandler (#57391)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/57391
Test Plan: Imported from OSS
Reviewed By: ngimel
Differential Revision: D28151601
Pulled By: ejguan
fbshipit-source-id: 34814197d2f068cab0c7ca2330152ad588eb1ef0
