Improve Delayer DSL (#8645)

* Improve Delayer DSL

Move `groupId` option from a `delay()` method arg to the `DelayerEndpointSpec`
to make it cleaner from code reading perspective
* Expose new DSL method based on just a `DelayerEndpointSpec` for Kotlin &v Groovy
* Deprecate multi-arg `delay()` methods in favor of `Consumer<DelayerEndpointSpec>`-based

* * Fix language and code style

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

@@ -801,7 +801,8 @@ public class IntegrationFlowTests {
 			return IntegrationFlow.from("bridgeFlow2Input")
 					.bridge(c -> c.autoStartup(false).id("bridge"))
 					.fixedSubscriberChannel()
-					.delay("delayer", d -> d
+					.delay(d -> d
+							.messageGroupId("delayer")
 							.delayExpression("200")
 							.advice(this.delayedAdvice)
 							.messageStore(this.messageStore()))

spring-integration-core/src/test/kotlin/org/springframework/integration/dsl/KotlinDslTests.kt

@@ -320,7 +320,10 @@ class KotlinDslTests {
 				wireTap {
 					channel { queue("wireTapChannel") }
 				}
-				delay("delayGroup") { defaultDelay(100) }
+				delay {
+					messageGroupId("delayGroup")
+					defaultDelay(100)
+				}
 				transform<String> { it.uppercase() }
 			}