Fix OPENDJ-1270: Avoid unnecessary DNS lookups when performing bind requests

* rename LDAP{ConnectionFactory|Listener}.getHostname() to getHostName()
* change LDAP{ConnectionFactory|Listener}.getAddress() to return InetSocketAddresses
* change constructors to only accept InetSocketAddresses instead of more generic SocketAddress
* ensure that LDAP{ConnectionFactory|Listener}.getAddress() returns an address which represents the exact socket address passed in during construction, except in the case where a listener is created with port 0 where we return the selected port
* modify LDAP{ConnectionFactory|Listener}.getHostName() to return whatever was provided as the host name during construction, which may have been a raw IP address. This avoids attempts to perform a reverse DNS lookup in the case where the provided host name was an IP address and, in particular, avoids DNS timeouts in environments where there is no DNS
* modify client bind processing to use LDAPConnectionFactory.getHostName() as the server name used for SASL authentication, and avoid any potential DNS delays as a result.