CDAP-556 Communication over SSL between AuthServer and LDAP

This allows the enabling of communication between the AuthServer and an LDAP instance over SSL. 

By default, certificate checking is enabled. You can override this property by setting ``ldapsVerifyCertificate`` in the configuration.

Docs will be updated separately.
The SSL implementation of this needs the port to set up the listener in it's ``@BeforeClass`` setup method. Originally it was being set in ``getConfiguration``, and thus was not available to configure the listener.