Plugin that checks if user has permissions to publish pages/posts/custom post types. If they don't, it will send it to review by someone who can
Copy the plugin files to
Activate plugin from Plugins page or Network Activate for multisite
Go to Settings -> Approval Workflow to adjust plugin settings
You must ensure the users you want to approve are in a role that does not have publish_page (or any publish permissions for other post types) permissions.