Some Java DSL improvements

* Register `BeanDefinition`s for DSL components.
That way we get a gain when the `BeanDefinition` is involved,
e.g. Spring Cloud Function uses this approach to determine the generics
of the target `Function` class
* This programmatic `BeanDefinition` registration approach
(available since SF-5.0) allows us to avoid some manual lifecycle processes:
bean initialization, autowiring, event listener registration etc.
* Rework `IntegrationFlowContext` to register and remove `BeanDefinition`s as well
* Remove unused `registerComponents`  flag from the `StandardIntegrationFlow`.
With the proper logic in the `IntegrationFlowContext` it does not make sense any more
* Remove redundant `AnnotationGatewayProxyFactoryBean` in the `IntegrationFlows`;
populate `defaultRequestChannel` directly to the `GatewayProxyFactoryBean` instance
* Add an overloaded `IntegrationFlows.from(Class, String)` to allow to specify an
explicit bean name for the target gateway proxy
* Extract and populate bean name from the `@MessagingGateway.name()` in the
`AnnotationGatewayProxyFactoryBean`
* Stop lifecycles in the `AmqpTests` after using for proper test suit shutdown

spring-integration-core/src/test/java/org/springframework/integration/dsl/flows/IntegrationFlowTests.java

@@ -444,6 +444,7 @@ public class IntegrationFlowTests {
 	}
 
 	@Autowired
+	@Qualifier("errorRecovererFunction")
 	private Function<String, String> errorRecovererFlowGateway;
 
 	@Test
@@ -789,7 +790,7 @@ public class IntegrationFlowTests {
 
 		@Bean
 		public IntegrationFlow errorRecovererFlow() {
-			return IntegrationFlows.from(Function.class)
+			return IntegrationFlows.from(Function.class, "errorRecovererFunction")
 					.handle((GenericHandler<?>) (p, h) -> {
 						throw new RuntimeException("intentional");
 					}, e -> e.advice(retryAdvice()))