add port management function

As for port,there are only one function on the project dashboard,which is "edit". onece an instance is launched, no more port(interface) could be attached to it via horizon.actually, the novaclient has supported this feature in the shell command.so in order to support this feature, we should add port management on the network dashboard, port can be created by user ,as well as be attached to an instance and be dettached.