Add remove from followers api (#16864)

* Add followed_by? to account_interactions

* Add RemoveFromFollowersService

* Fix AccountBatch to use RemoveFromFollowersService

* Add remove from followers API

config/routes.rb

@@ -459,6 +459,7 @@ Rails.application.routes.draw do
         member do
           post :follow
           post :unfollow
+          post :remove_from_followers
           post :block
           post :unblock
           post :mute