refs https://github.com/TryGhost/Team/issues/1598
- added `<GhPostBookmark>` card for displaying a bookmark card style representation of a post
- updated designsandbox route to include it for easier styling without needing to constantly go through the publish flow to see changes whilst styling
- updated publish flow complete step to render a bookmark card if a post/page was published
- added `{{post-author-names}}` helper so the author name concatenation logic can be re-used across the posts list and bookmark component
no issue
- ran the `ember-native-class-codemod` codemod to convert just the route classes to native class syntax and performed some minor manual cleanup
- modern Ember uses native classes rather than EmberObject-based objects, this brings us closer to normalizing our code style across the codebase
- skipped the Application route as that requires deeper testing with a replacement for the `ShortcutsRoute` mixin