no issue
- preparation for using `ember-pikaday` that utilizes `ember-cli-moment-shim`
- removes usage of `moment` global
- removes custom imports of `moment` and `moment-timezone` libraries
closes https://github.com/TryGhost/Ghost/issues/8055
- use `expired` if the date is in the past, otherwise `expires`
- fix mirage factories to use `moment.valueOf` instead of `moment.unix` for invite `expires` attributes
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
