Remove inactive reviewers from `CODEOWNERS`

[henrif75]

@henrif75, related to this, I suggest we remove people from the CODEOWNERS file if we don't see them in ~3 months or so. That will help keep the list of reviewers focused and it will avoid the situation where everybody thinks someone else will deal with the review.

Originally posted by @mgeisler in #1343 (comment)

[mgeisler]

I think this was done with #1386.

[henrif75]

I did some basic cleanup there, but didn't check inactive users.

[mgeisler]

Okay, I guess I would prefer closing this issue and then just do it every ~3 months or so if that's okay with you?