In deployment-novncproxy.yaml, it set hostNetwork = true.
In some cases, we may want to let it use cluster network instead of
hostNetwork.
We'd better add a config item, so that client can override it to use
cluster network based on an operators preferences.
Story: 2006490
Task: 36439
Change-Id: Ia235d4e9542bd9242f9d2713ad1e67870f3016e2
Signed-off-by: zhipengl <zhipengs.liu@intel.com>