Red crosses implied that it was bad/unexpected that certain features
were not enabled. In reality, they are options, so showing a green
or grey power-off icon is more appropriate.
Add status of timeline preview as well
Fix sample accounts changing too frequently due to wrong query
Sample accounts are intended to be sorted by popularity
* Add instance-wide setting to disable profile directory
Fixes#9496
When the profile directory is disabled:
- The “discoverable” setting is hidden from users
- The “profile directory” link is not shown on public pages
- /explore returns 404
* Move Setting.profile_directory check to a before_action filter
