Backup Appreciation Day 2017-08-03

It's that time again, backup appreciation day! The goal of this day is to ensure our backups are in fact actually backing up. There are several things to test here.

• Restore WAL-E backup for our production DB (relevant documentation)
• Restore of a secondary servers with WAL-E w/GPG encryption (relevant documentation):
• dev.gitlab.com
• chef.gitlab.com
• Test restore of an Azure snapshot (relevant documentation)
• Test restore of PackageCloud database (relevant documentation)

Automate steps that can be automated. Previous B.A.D.: #2166 (closed).

This time, the resulting server with our production DB should not be cleaned, but rather left to @yorickpeterse for experiments as part of #2392.