RemoteFollowConnectProfile: when the plugin is "one url away" from redirecting to the remote follower instance; federation plugins must find and retrieve the url for redirection
- User $target local user to be followed
- string $profile remote follower's ID
- string|null &$url url for redirection

RemoteFollowPullProfile: when the plugin needs to pull the remote profile from its uri; federation plugins must pull, store and retrieve the profile's local object
- string $uri the remote profile's uri
- null|Profile &$profile pulled profile