Resolve the review process overhead

[mattmoor]

Expected Behavior

As a reviewer, I should be able to approve a change with a single action, one of:

1. GitHub review
2. /lgtm and/or /approve comment

Actual Behavior

Our concoction of process that straddles Prow (OWNERS) and Github (CODEOWNERS) features means we have to do 2-3 of these things (possibly from multiple reviewers) for tide to merge things.

Maybe I'm "holding it wrong", or we're using Prow incorrectly, but I'd like to streamline this process so it's crystal clear what reviewers need to do to bless a PR.

cc @adrcunha @fejta @cjwagner for suggestions.

[mattmoor]

@vaikas-google pointed me at this

[adrcunha]

There's a discussion about this in #543. Grant wrote an interesting analysis and possible compromise given the restrictions. I don't have any strong opinion about this.

[mattmoor]

Great thanks. let's track this there, sorry for the noise.