CI Utilisation and system efficiency

[David Edmundson]

>Realistically merge requests shouldn't be proposed until people are ready to get something reviewed and merged in...

That's not realistic with how it is on the frontlines. The earlier we
share feedback the better, and reviews can take many many iterations.

There's a "CI_MERGE_REQUEST_APPROVED"  variable which seems to match
what I think we're after?
Then we're running it only when the reviewer thinks it's ready.

David