Collapse/hide unpublished comments

Spin-off from #660960: Hide '+1 Subscribe' comments

"+1/subscribe" comments are getting unpublished. They're not visible for regular users anymore, but privileged users still see them.

Since other comments from trolls (hi-jacking an important issue) and security-related comments are getting unpublished, too, it would be ideal if unpublished comments would be collapsed (instead of hiding them entirely), so they can be expanded if the desired.