refs https://github.com/TryGhost/Ghost/issues/7860
- load 30 posts per page
- clean up unnecessary styles, match class name to component name
- start moving towards desired content/styles end goal
no issue
- add loading substates for all routes that previously blocked transitions until their model had finished loading
- enables immediate response on navigation click
- loading templates include the title bar to provide immediate indication of which page is loading
- loading templates include a new `{{gh-loading-spinner}}` component that will only show the spinner after 200ms to avoid flashing a spinner for users on fast connections
- updated Version Mismatch tests to match new behaviour of intermediate transitions when navigating
