Official Offline support document for Kubespray.

Kubespay v2.10.4 - https://github.com/kubernetes-sigs/kubespray/blob/v2.10.4/docs/downloads.md#offline-environment

Open questions:

• Is v2.11 actually support caching in offline mode? Is there is any benefit for ICN by using v2.11 in offline mode? Try now, we are using v2.10.4 only.
• Setting up the https_server in the bootstrap machine and set the offline environment  - https://github.com/kubernetes-sigs/kubespray/blob/v2.10.4/docs/downloads.md#offline-environment

 Deliverable: Test the Kubespray 2.10.4 and Kube version v1.14.3