Provide the Ability for Ambari To Upgrade From One Vendor's Stack To Another

Ambari currently cannot support full stack upgrades between stacks which have different names. For example, if you have FOO-1.0 installed and you want to upgrade to BAR-2.0, this is currently not possible. There are several top-level work items for this:

• Removing assumptions about stack names when dealing with upgrades and creating commands

• Allowing multiple stacks with different names to be registered and exposed via the web client

• Providing an example stack which supports upgrades from a different vendor's stack

• Support for stack tools on a per-stack basis.