NMS-6667 and NMS-6668: Initial revision of LdapMonitor and LdapsMonitor

http://issues.opennms.org/browse/NMS-6667
http://issues.opennms.org/browse/NMS-6668
- | `dn` | The distinguished name to use is authenticated is needed. | optional | `-`
+| `dn` | The distinguished name to use if authentication is needed. | optional | `-`