Add 'archived' column to the 3 reply_to models

Added a new boolean column, `archived`,  with a default of False to the
three models which are used to specify the 'reply to' address for
notifications:
 * ServiceEmailReplyTo
 * ServiceSmsSender
 * ServiceLetterContact

tests/app/dao/test_service_sms_sender_dao.py

@@ -58,6 +58,7 @@ def test_dao_add_sms_sender_for_service(notify_db_session):
     assert len(service_sms_senders) == 2
     assert service_sms_senders[0].sms_sender == 'testing'
     assert service_sms_senders[0].is_default
+    assert not service_sms_senders[0].archived
     assert service_sms_senders[1] == new_sms_sender