Batched remove status service (#3735)

* Make Pubsubhubbub::DistributionWorker handle both single stream entry
arguments, as well as arrays of stream entries

* Add BatchedRemoveStatusService, make SuspendAccountService use it

* Improve method names

* Add test

* Add more tests

* Use PuSH payloads of 100 to have a clear mapping of
1000 input statuses -> 10 PuSH payloads

It was nice while it lasted

app/services/suspend_account_service.rb

@@ -17,9 +17,8 @@ class SuspendAccountService < BaseService
   end
 
   def purge_content
-    @account.statuses.reorder(nil).find_each do |status|
-      # This federates out deletes to previous followers
-      RemoveStatusService.new.call(status)
+    @account.statuses.reorder(nil).find_in_batches do |statuses|
+      BatchedRemoveStatusService.new.call(statuses)
     end
 
     [