refs #9178 - move tests as well
refs #9178 - avoid importing 4 modules (logging, errors, events and i18n) - simply require common in each file
refs #9178
refs #9178 - move express apps to one place (called `web`) - requires https://github.com/TryGhost/Ghost-Admin/pull/923 - any further improvements are not part of this PR - this PR just moves the files and ensures the paths are up-to-date