Add JNDI Sample

Add a sample application that can be deployed to WildFly to demonstrate
how JTA can be used when running in a application server.

See gh-947

spring-boot-samples/pom.xml

@@ -40,6 +40,7 @@
 		<module>spring-boot-sample-jetty</module>
 		<module>spring-boot-sample-jta-atomikos</module>
 		<module>spring-boot-sample-jta-bitronix</module>
+		<module>spring-boot-sample-jta-jndi</module>
 		<module>spring-boot-sample-liquibase</module>
 		<module>spring-boot-sample-parent-context</module>
 		<module>spring-boot-sample-profile</module>