JIRA: https://jira.spring.io/browse/INT-4328
Add support for sending `ErrorMessage`s to the return and nack channels.
**cherry-pick to 4.3.x, but change default EMS to null (will require minor adjustment to test - set the EMS in `adapterWithReturnsAndErrorMessageStrategy`)**
# Conflicts:
# spring-integration-amqp/src/main/java/org/springframework/integration/amqp/outbound/AbstractAmqpOutboundEndpoint.java
# spring-integration-amqp/src/main/java/org/springframework/integration/amqp/support/AmqpMessageHeaderErrorMessageStrategy.java
# spring-integration-amqp/src/test/java/org/springframework/integration/amqp/outbound/AmqpOutboundEndpointTests.java
# spring-integration-amqp/src/test/java/org/springframework/integration/amqp/outbound/AsyncAmqpGatewayTests.java
# spring-integration-core/src/main/java/org/springframework/integration/support/DefaultErrorMessageStrategy.java
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