Ability to read reports

Reports are special activities that can be federated. They are used to alert an admin of an instance of a problem with a user or a post. We need a way to view these in AdminFE. They are literally activities, so we can treat them like regular statuses/posts and show them in a "timeline". Admins could also "reply" to the report to leave notes.

We likely have to build out a BE API endpoint to support fetching the reports.