Support Offline Stack Upgrades In a Cluster

The purpose of this Epic is to track the work required for offline upgrades. The general workflow will be:

• Create a host (VM) that is NOT part of a cluster that duplicates the hostname.
• Install bits for an upgraded version of the software on a cluster.
• Make Ambari aware that a new version is installed on the cluster.
• Host-by-host, instruct Ambari to stop services for a host.
• Once the components are stopped, stop the agent on the host.
• After removing the host from the cluster, bring up the new host with the new bits pre-installed.
• Ambari should accept the versions reported by the new host.