Move OpInfos for torch.fft into `opinfo.definitions` (#83276)
Ref #82518
This moves the `op_db` entries into `opinfo/definitions/fft.py` and
also appends them to `common_methods_invocations.op_db` so existing
users are unaffected by this change.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83276
Approved by: https://github.com/albanD
