There is a hack to achieve this goal.
You need to use the "Moderation" app for this purpose. If you want to have "all" content to be sent for moderation first, you can define the "Minimum Reputation" score for each content/activity a very high number, like 20,000. And because no user has such high reputation score in your community, therefore, the contents from all users will be sent for moderation before getting published.
How to define these rules for moderation and what it means? You can learn more here93 and here97.
