GH-718 Improve support for Function bean definition

Added sample for functional bean definition

spring-cloud-function-samples/function-functional-sample-aws/src/main/java/example/FunctionConfiguration.java

@@ -0,0 +1,30 @@
+package example;
+
+import java.util.function.Function;
+
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.cloud.function.context.FunctionRegistration;
+import org.springframework.cloud.function.context.FunctionType;
+import org.springframework.context.ApplicationContextInitializer;
+import org.springframework.context.support.GenericApplicationContext;
+
+@SpringBootConfiguration
+public class FunctionConfiguration implements ApplicationContextInitializer<GenericApplicationContext> {
+
+	/*
+	 * You need this main method (empty) or explicit <start-class>example.FunctionConfiguration</start-class>
+	 * in the POM to ensure boot plug-in makes the correct entry
+	 */
+    public static void main(String[] args) {
+    	// empty unless using Custom runtime at which point it should include
+    	// FunctionalSpringApplication.run(FunctionConfiguration.class, args);
+    }
+
+    @Override
+    public void initialize(GenericApplicationContext context) {
+    	Function<String, String> function = (str) -> str + str.toUpperCase();
+    	context.registerBean("uppercase", FunctionRegistration.class,
+				() -> new FunctionRegistration<>(function).type(
+						FunctionType.from(String.class).to(String.class)));
+    }
+}