Rebuild Post Settings Menu; Connect to DS Models

Closes #2845, Depends on #2889, Ref #1351

- Renamed `gh-blur-text-field` to `gh-blur-input`
- Changed Editor.hbs title input to `gh-blur-input` component.
- Changed `post-settings-menu-view` to a component.
- Added `verifyTimeStamp` function to add a `" 12:00"` timestamp to strings
  without one in `utils/date-formatting`.
- Blurring title field on editor view triggers a slugPlaceholder update
- Changed `post-settings-menu` to extend `gh-popover`