Choose external network while creating a new network

[lorenzotomasini]

While creating a new network, in any OpenStack scenario, there is no way to specify which external network should be used as "externalGateway", in the openstack plugin code:

log.info("Create Router on " + vimInstance.getName());
    return os.networking()
        .router()
        .create(
            Builders.router()
                .name("openbaton-router")
                .adminStateUp(true)
                .externalGateway(getExternalNet(vimInstance).getExtId())
                .build());

Thus we need to extend the model and add a field in the Network/Subnet class in order to be able to make that choice.

+ @RuthDevlaeminck