Parent commit allow custom secure HYPERKUBE_IMAGE_REPO (which can also
be a local registry). Here we implement INSECURE_REGISTRY_URL which
allow settings custom insecure registry for Kubernetes infra components.
It also enable the insecure registry for Docker daemon.
Partially-Implements: blueprint coreos-best-pratice
Partially-Implements: blueprint support-insecure-registry
Change-Id: If00afa2e8a9100546301f9a1f161daed6e3ffc4f
Michal Nasiadka