Session disconnect delay support configurable

[straybirdzls]

Currently , Session disconnect delay is fixed as below:

public class SessionServerConnectionFactory {
    private static final Logger            LOGGER                      = LoggerFactory
                                                                           .getLogger(SessionServerConnectionFactory.class);

    private static final int               DELAY                       = 30 * 1000;
    private static final Map               EMPTY_MAP                   = new HashMap(0);