chore: Add CODEOWNERS file

[matsales28]

As part of our work to easily identify the maintainers of our open source projects, this PR adds a CODEOWNER file.

What it does:

Automatically include people as reviewers on pull requests Provide a clear reference of who should be answering questions and making decisions Make it easy to search for projects which need a new owner when needed

[vsppedro]

Thank you for considering me, but I don't believe I should be added as a Codeowner. While I'm happy to assist when I can, the Codeowner role requires someone with more availability than I can currently commit to. @matsales28