Minor Description
Currently Livy does not support communicating to an Active Directory through LDAP since its actual config for it is hardcoded (https://github.com/apache/incubator-livy/blob/master/server/src/main/scala/org/apache/livy/server/auth/LdapAuthenticationHandlerImpl.scala#L131).
A good way to solve this issue would be to have more parameters to customize the search string and the how to specify the user attribute field ('sAMAccountName' for AD as an example)
