.github: Add CODEOWNERS and REVIEWERS

Add CODEOWNERS and REVIEWRS based on Maintainers.txt
along with github actions to assign reviewers to a PR
and verify that any updates to CODEOWNERS, REVIEWERS or
Maintainers.txt are in sync.

Also add CODEOWNERS and REVIEWERS for .github directory.

Signed-off-by: Michael D Kinney <[email protected]>

Author: mdkinney