no issue
- part of ember upgrades
- removed all unnecessary usage of `.get`
- cleaned up imports where we had imports from the same module across multiple lines
- standardized on importing specific computed helpers rather than using `computed.foo`
- switched tests from using `wait()` to `settled()`
no issue
- adds `whats-new` service that fetches the changelog from ghost.org and exposes the latest changelog entries
- trigger a background fetch of the changelog from ghost.org when first loading the admin when logged in, or after signing in
- adds a "What's new" menu item next to the user popup menu
- adds an indicator to the user menu button and what's new menu item if there are unseen changelog entries
- closing the changelog modal will update the "last seen date", clearing both indicators
