FEATURE: Create hidden posts for received spam emails (#6010)

* Add possibility to add hidden posts with PostCreator

* FEATURE: Create hidden posts for received spam emails

Spamchecker usually have 3 results: HAM, SPAM and PROBABLY_SPAM
SPAM gets usually directly rejected and needs no further handling.
HAM is good message and usually gets passed unmodified.
PROBABLY_SPAM gets an additional header to allow further processing.
This change addes processing capabilities for such headers and marks
new posts created as hidden when received via email.

lib/post_creator.rb

@@ -36,6 +36,7 @@ class PostCreator
   #                             wrap `PostCreator` in a transaction, as the sidekiq jobs could
   #                             dequeue before the commit finishes. If you do this, be sure to
   #                             call `enqueue_jobs` after the transaction is comitted.
+  #   hidden_reason_id        - Reason for hiding the post (optional)
   #
   #   When replying to a topic:
   #     topic_id              - topic we're replying to
@@ -62,6 +63,7 @@ class PostCreator
     opts[:title] = pg_clean_up(opts[:title]) if opts[:title] && opts[:title].include?("\u0000")
     opts[:raw] = pg_clean_up(opts[:raw]) if opts[:raw] && opts[:raw].include?("\u0000")
     opts.delete(:reply_to_post_number) unless opts[:topic_id]
+    opts[:visible] = false if opts[:visible].nil? && opts[:hidden_reason_id].present?
     @guardian = opts[:guardian] if opts[:guardian]
 
     @spam = false
@@ -454,6 +456,12 @@ class PostCreator
       post.custom_fields = fields
     end
 
+    if @opts[:hidden_reason_id].present?
+      post.hidden = true
+      post.hidden_at = Time.zone.now
+      post.hidden_reason_id = @opts[:hidden_reason_id]
+    end
+
     @post = post
   end