Revert "Revert "Reducing number of pings""

This reverts commit 3a6baa97444c08082b5f7b847261a9d8f1a58778.
DomainGroupedViolationsHandler: 'NoneType' object is not iterable
Config material girl to use test cache
Remove unneccessary handlers from handlers.domains
DomainReviewsHandler: Removing unnecessary code
Domain model: Fixed get_active_reviews()

Fixed ordering