refactor: move senders in to app/senders/

app/lib/dns_resolver.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "resolv"
+
 class DNSResolver
 
   attr_reader :nameservers

app/lib/message_dequeuer/incoming_message_processor.rb

@@ -163,11 +163,11 @@ module MessageDequeuer
 
       case queued_message.message.endpoint
       when SMTPEndpoint
-        sender = @state.sender_for(Postal::SMTPSender, queued_message.message.recipient_domain, nil, servers: [queued_message.message.endpoint])
+        sender = @state.sender_for(SMTPSender, queued_message.message.recipient_domain, nil, servers: [queued_message.message.endpoint])
       when HTTPEndpoint
-        sender = @state.sender_for(Postal::HTTPSender, queued_message.message.endpoint)
+        sender = @state.sender_for(HTTPSender, queued_message.message.endpoint)
       when AddressEndpoint
-        sender = @state.sender_for(Postal::SMTPSender, queued_message.message.endpoint.domain, nil, force_rcpt_to: queued_message.message.endpoint.address)
+        sender = @state.sender_for(SMTPSender, queued_message.message.endpoint.domain, nil, force_rcpt_to: queued_message.message.endpoint.address)
       else
         log "invalid endpoint for route (#{queued_message.message.endpoint_type})"
         create_delivery "HardFail", details: "Invalid endpoint for route."

app/lib/message_dequeuer/outgoing_message_processor.rb

@@ -135,7 +135,7 @@ module MessageDequeuer
       @result = @state.send_result
       return if @result
 
-      sender = @state.sender_for(Postal::SMTPSender,
+      sender = @state.sender_for(SMTPSender,
                                  queued_message.message.recipient_domain,
                                  queued_message.ip_address)