Summary:
Pull Request resolved: https://github.com/pytorch/kineto/pull/626

Follow the BSD License OSS guidance, and fix the copyright headers. Remove `Confidential and proprietary.` and `All rights reserved.` and replace with BSD license.

Also, replace Facebook with `Meta Platforms, Inc. and affiliates`.

Test Plan: These are comment changes mostly.

Reviewed By: yns88, jurajh-fb

Differential Revision: D37467493

Pulled By: aaronenyeshi

fbshipit-source-id: a9be8b2c324b705753c047e9f7e41d91f16323bc