Add and use CODEOWNERS (or other similar tool)

[noelmiller]

We do not have CODEOWNERS implemented on all of our repositories. It would be good to have this implemented everywhere as a standard or use a tool that centralizes it like: https://github.com/cncf/clomonitor

This issue is for discussion on how we would like to move forward.

[castrojo]

Ok I think we can use prow for this but we need something liteweight. Got this recommended to me but it needs a maintenance release at a minimum. I'll ping john and see if he can give it a bit of love: https://github.com/marketplace/actions/prow-github-actions