closes: https://github.com/TryGhost/Ghost/issues/15506
- The sidebar items that don't open the editor were missing some relative current-when attributes so the nested views weren't considered "active".
refs TryGhost/Team#1826
- allows staff users to manage their email alert settings behind the flag
- only owner and admin users are able to toggle their email alerts
refs https://github.com/TryGhost/Team/issues/1586
- added test helper for enabling/disabling members and helpers for disabling mailgun and newsletters
- added `loginAsRole` helper that alleviates duplication of user+role creation and also handles log-out before log-in so it's easier to mix different role tests within a block that has a default role setup in `beforeEach()`
- cleaned up editor tests that were skipped due to using the old publish flow
- added `Publish flow` acceptance test suite with an initial batch of tests
