Add LDAP sample

Add an LDAP sample application.

See gh-7733

spring-boot-samples/pom.xml

@@ -38,6 +38,7 @@
 		<module>spring-boot-sample-data-elasticsearch</module>
 		<module>spring-boot-sample-data-gemfire</module>
 		<module>spring-boot-sample-data-jpa</module>
+		<module>spring-boot-sample-data-ldap</module>
 		<module>spring-boot-sample-data-mongodb</module>
 		<module>spring-boot-sample-data-neo4j</module>
 		<module>spring-boot-sample-data-redis</module>