refactor: move lib/postal/received_header to app/lib/received_header

lib/postal/received_header.rb

@@ -1,32 +0,0 @@
-# frozen_string_literal: true
-
-module Postal
-  class ReceivedHeader
-
-    OUR_HOSTNAMES = {
-      smtp: Postal.config.dns.smtp_server_hostname,
-      http: Postal.config.web.host
-    }.freeze
-
-    class << self
-
-      def generate(server, helo, ip_address, method)
-        our_hostname = OUR_HOSTNAMES[method]
-        if our_hostname.nil?
-          raise Error, "`method` is invalid (must be one of #{OUR_HOSTNAMES.join(', ')})"
-        end
-
-        header = "by #{our_hostname} with #{method.to_s.upcase}; #{Time.now.utc.rfc2822}"
-
-        if server.nil? || server.privacy_mode == false
-          hostname = DNSResolver.local.ip_to_hostname(ip_address)
-          header = "from #{helo} (#{hostname} [#{ip_address}]) #{header}"
-        end
-
-        header
-      end
-
-    end
-
-  end
-end