Remove Salmon and PubSubHubbub (#11205)

* Remove Salmon and PubSubHubbub endpoints

* Add error when trying to follow OStatus accounts

* Fix new accounts not being created in ResolveAccountService

app/workers/pubsubhubbub/unsubscribe_worker.rb

@@ -5,11 +5,5 @@ class Pubsubhubbub::UnsubscribeWorker
 
   sidekiq_options queue: 'push', retry: false, unique: :until_executed, dead: false
 
-  def perform(account_id)
-    account = Account.find(account_id)
-    logger.debug "PuSH unsubscribing from #{account.acct}"
-    ::UnsubscribeService.new.call(account)
-  rescue ActiveRecord::RecordNotFound
-    true
-  end
+  def perform(account_id); end
 end