JIRA: https://jira.spring.io/browse/INT-3504 * Deprecate `AmqpHeaders` and extend it from `org.springframework.amqp.support.AmqpHeaders` for backward compatibility * Change AMQP dependency to `1.4.0` * Remove usage of deprecated `spring_reply_correlation` and `spring_reply_to` AMQP headers * Fix syslog `DefaultMessageConverter` JavaDoc Reformat code