Set snowflake IDs for backdated statuses (#5260)

- Rename Mastodon::TimestampIds into Mastodon::Snowflake for clarity
- Skip for statuses coming from inbox, aka delivered in real-time
- Skip for statuses that claim to be from the future

app/services/process_feed_service.rb

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
 class ProcessFeedService < BaseService
-  def call(body, account)
+  def call(body, account, options = {})
+    @options = options
+
     xml = Nokogiri::XML(body)
     xml.encoding = 'utf-8'
 
@@ -20,7 +22,7 @@ class ProcessFeedService < BaseService
   end
 
   def process_entry(xml, account)
-    activity = OStatus::Activity::General.new(xml, account)
+    activity = OStatus::Activity::General.new(xml, account, @options)
     activity.specialize&.perform if activity.status?
   rescue ActiveRecord::RecordInvalid => e
     Rails.logger.debug "Nothing was saved for #{activity.id} because: #{e}"