GH-718 Improve support for Function bean definition

Added sample for functional bean definition

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

@@ -2,7 +2,6 @@ package example;
 
 import java.util.function.Function;
 
-import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
 
@@ -10,11 +9,12 @@ import org.springframework.context.annotation.Bean;
 public class FunctionConfiguration {
 
 	/*
-	 * You need this main method or explicit <start-class>example.FunctionConfiguration</start-class>
+	 * 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) {
-		SpringApplication.run(FunctionConfiguration.class, args);
+		// empty unless using Custom runtime at which point it should include
+		// SpringApplication.run(FunctionConfiguration.class, args);
 	}
 
 	@Bean