BAEL-4915 added in the code for the article on long polling (#10660)

* BAEL-4915 added in the code for the article on long polling using DeferredResult

* BAEL-4915 altered package for long polling article due to previous package being full

Co-authored-by: Liam Garvie <liamgarvie@Liams-MacBook-Pro.local>

spring-web-modules/spring-rest-http/pom.xml

@@ -24,6 +24,10 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-validation</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-webflux</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-oxm</artifactId>