Netty server should close idle connections.

Netty server adapter should handle client idle when there is no traffic within a certain amount of time.
Currently, if client open connection without sending any message. The connection will keep open.
If there is no Connection: close header, the connection will keep open.
Unless there is "Connection: close" header, they always require client to close.
For Jetty, the default idleTimeOut for Connector is 30 seconds.
Even I can add an IdleHandler to NettyJaxrsServer.addChannelHandlers, it's better to build in NettyJaxrsServer and add setter and attribute for idleTimeOut.