[Analytics] Superset going down for a few hours

Team: Superset will be going down for a few hours today as we rollback the update we were trying to do. It turns out that the newest versions of superset are VERY non backwards compatible, they use python 3.6 which is not available on our debian distro and they introduce a bunch of other bugs. We will be working on our fork from now on so we have a more stable basis for changes: https://github.com/wikimedia/incubator-superset More updates here: https://phabricator.wikimedia.org/T211605 Thanks, Nuria