Gamification follow up
Use standalone leaderboard page component for both creator and presentation
Also delete creators LeaderboardPageComponent
since it's no longer used.
Add refresh interval to content group leaderboard page
Refresh participants content leaderboard if there are incoming answers
Preparation: Use content group resolver in participants content carousel
Stop allowing to edit timer for already answered contents
Reload content in presentation mode if content has duration and answers have been deleted
Closes #1298 (closed)