implemented basic ldap auth configuration ui

Change-Id: I4553b080716ec7395996f08e1202c12ac0469384
Reviewed-on: http://review.couchbase.org/44124
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>