mod reports: enable reporting for members, add dmail reporting.

* Add ability to report dmails.
* Enable reports for comments, forum posts, and dmails.
* Allow Members to send reports.
* Don't allow users to report the same thing twice.

app/models/forum_topic.rb

@@ -177,8 +177,4 @@ class ForumTopic < ApplicationRecord
   def update_orignal_post
     original_post&.update_columns(:updater_id => updater.id, :updated_at => Time.now)
   end
-
-  def viewable_moderation_reports
-    CurrentUser.is_moderator? ? moderation_reports.recent : []
-  end
 end