Folders

This PR brings in further integration for OAE in the following aspects:
 - Activities
 - Search
 - Previews
 - REST Docs
 - Extra functionality such as updating, deleting, ..
This function is seemingly the opposite of the `assertFeedContainsActivity` function. However, `assertFeedContainsActivity` also checks the verb, actorId, etc. We should make it clearer that `assertFeedContainsActivity` does a stricter check than this function