Move Embedded Redis classes to org.springframework.session.redis.embedded

This prevents the embedded redis from being picked up in ComponentScan
in any of the samples unless the @EnableEmebeddedRedis annotation is used.

Polish gh-184

samples/httpsession-xml/src/main/webapp/WEB-INF/spring/session.xml

@@ -7,7 +7,7 @@
 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
 
 	<!-- tag::beans[] -->
-	<bean class="sample.EmbeddedRedisConfiguration"/> <!--1-->
+	<bean class="org.springframework.session.redis.embedded.EmbeddedRedisConfiguration"/> <!--1-->
 
 	<!--2-->
 	<context:annotation-config/>