PromoteImageReviewTask

@scottrabin 
This task suffered from being executed on wikis that didn't have the required extensions enabled. This refactor makes it pretty much exactly like https://github.com/Wikia/app/blob/dev/extensions/wikia/ImageReview/modules/PromoteImage/PromoteImageReviewTask.php.
Yah, @drsnyder had a comment about be getting too excited with instantiating classes here and making this hard to read, which I think is a valid point. Maybe this is too extreme in the other direction?