Add native support for RSocketExchange.

This commit introduces new AOT processors that look for
`@RSocketExchange` annotated methods on interfaces implemented by beans
and registers reachability metadata accordingly:

* JDK proxies for the beans themselves
* invocation reflection for annotated methods
* binding reflection for arguments and return types

This allows to compile such clients to Native Images.

Closes gh-29877

spring-messaging/spring-messaging.gradle

@@ -34,6 +34,7 @@ dependencies {
 	testImplementation("org.skyscreamer:jsonassert")
 	testImplementation("org.xmlunit:xmlunit-assertj")
 	testImplementation("org.xmlunit:xmlunit-matchers")
+	testImplementation(project(":spring-core-test"))
 	testRuntimeOnly("com.sun.activation:jakarta.activation")
 	testRuntimeOnly("com.sun.xml.bind:jaxb-core")
 	testRuntimeOnly("com.sun.xml.bind:jaxb-impl")