Add a spam check (#11217)

* Add a spam check

* Use Nilsimsa to generate locality-sensitive hashes and compare using Levenshtein distance

* Add more tests

* Add exemption when the message is a reply to something that mentions the sender

* Use Nilsimsa Compare Value instead of Levenshtein distance

* Use MD5 for messages shorter than 10 characters

* Add message to automated report, do not add non-public statuses to
automated report, add trust level to accounts and make unsilencing
raise the trust level to prevent repeated spam checks on that account

* Expire spam check data after 3 months

* Add support for local statuses, reduce expiration to 1 week, always create a report

* Add content warnings to the spam check and exempt empty statuses

* Change Nilsimsa threshold to 95 and make sure removed statuses are removed from the spam check

* Add all matched statuses into automatic report

app/services/remove_status_service.rb

@@ -23,6 +23,7 @@ class RemoveStatusService < BaseService
         remove_from_hashtags
         remove_from_public
         remove_from_media if status.media_attachments.any?
+        remove_from_spam_check
 
         @status.destroy!
       else
@@ -142,6 +143,10 @@ class RemoveStatusService < BaseService
     redis.publish('timeline:public:local:media', @payload) if @status.local?
   end
 
+  def remove_from_spam_check
+    redis.zremrangebyscore("spam_check:#{@status.account_id}", @status.id, @status.id)
+  end
+
   def lock_options
     { redis: Redis.current, key: "distribute:#{@status.id}" }
   end