DEV: Improve phpBB3 import script (#15956)

* Optional import of custom user fields from phpBB 3.1+
* Optional import of likes from phpBB3
  Requires the phpBB "Thanks for posts" extension
* Fix import of bookmarks from phpBB3
* Update `created_at` of existing user
* Support mapping of phpBB forums to existing Discourse categories
  This is in addition to the ability of merging phpBB forums and importing into newly created Discourse categories.

script/import_scripts/base.rb

@@ -366,6 +366,7 @@ class ImportScripts::Base
       # try based on email
       if e.try(:record).try(:errors).try(:messages).try(:[], :primary_email).present?
         if existing = User.find_by_email(opts[:email].downcase)
+          existing.created_at = opts[:created_at] if opts[:created_at]
           existing.custom_fields["import_id"] = import_id
           existing.save!
           u = existing
@@ -630,6 +631,35 @@ class ImportScripts::Base
     [created, skipped]
   end
 
+  def create_likes(results, opts = {})
+    created = 0
+    skipped = 0
+    total = opts[:total] || results.count
+
+    results.each do |result|
+      params = yield(result)
+
+      if params.nil?
+        skipped += 1
+      else
+        created_by = User.find_by(id: user_id_from_imported_user_id(params[:user_id]))
+        post = Post.find_by(id: post_id_from_imported_post_id(params[:post_id]))
+
+        if created_by && post
+          PostActionCreator.create(created_by, post, :like, created_at: params[:created_at])
+          created += 1
+        else
+          skipped += 1
+          puts "Skipping like for user id #{params[:user_id]} and post id #{params[:post_id]}"
+        end
+      end
+
+      print_status(created + skipped + (opts[:offset] || 0), total, get_start_time("likes"))
+    end
+
+    [created, skipped]
+  end
+
   def close_inactive_topics(opts = {})
     num_days = opts[:days] || 30
     puts '', "Closing topics that have been inactive for more than #{num_days} days."