Fix CODEOWNERS format; Add Outside Collaborators - #62325

As a follow-up on CODEOWNERS assignment:

It looks like non-VMware employees will not be able to be assigned as code reviewers. GitHub discovered that their documentation was incorrect, and that a reviewer would need to have Write permissions to the repository for GitHub automation to work as expected. Due to only giving Outside Collaborators Read or Triage permissions, we will not be able to have CODEOWNERS automation for the salt repository that includes community members unless GitHub supports this or we try to find an alternative means.

Original GitHub docs (which were incorrect):

The people you choose as code owners must have read permissions for the repository. When the code owner is a team, that team must be visible and it must have write permissions, even if all the individual members of the team already have write permissions directly, through organization membership, or through another team membership.

New GitHub docs mention:

The people you choose as code owners must have write permissions for the repository. When the code owner is a team, that team must be visible and it must have write permissions, even if all the individual members of the team already have write permissions directly, through organization membership, or through another team membership.

At this point, the CODEOWNERS file will only be able to work with VMware-employees, and not community members. I'll leave this up to the open devs to modify as they see fit with VMware employees when it comes to review assignment.

More info:

• CODEOWNERS documentation claims that a user needs at least read access, but GitHub's built in linter claims the user needs write access github/docs#18984 (comment)

Related GitHub feature request has been opened:

• Feature Request: Allow users with Triage and/or Read Permissions to be supported by CODEOWNERS