closesTryGhost/Ghost#6985
- renames all date properties to end with `UTC`:
- `publishedAt` in `post` model
- `createdAt` in `post`, `role`, `subscriber`, `tag` and `user` model
- `updatedAt` in `post`, `role`, `subscriber`, `tag` and `user` model
- `unsubscribedAt` in `subscriber` model
- `lastLogin` in `user` model
- adds `attrs` transforms in matching serializers `post`, `tag` and `user`
- new serializers files for `subscribers` and `role` to add `attr` transforms
- adds unit tests for all serializers
- use two variables in `post-settings-menu` controller to handle blog-timezone adjusted date as well as UTC date
- Incorrect message was shown (Invitation sent instead of Invitation not sent)
- Correct colouring of message (new .description-error class)
- Correctly display lastLogin time
- Add colour classes
closes#5434
- remove transition away from team page to user page of authors
- hide invite button from authors
- hide invited users from authors
- adjusted gh-user-can and renamed to gh-user-can-admin
- hide password reset on owners profile from administrators
- hide input field for owner email from administrators pending api fix
- fix up tests
