Bug 7723 - merge or re-write host tagging into master / 2.2
Bug 7627 - Need more logging for Allocators
Bug 8317 - Add better resource allocation failure messages
Changes for Deployment Planner to use host and storagePool allocators to find deployment destination.
Also has the changes for host tag feature.
Improved the logging for allocators.
1. delete local storage when delete host
2. delete host detail when delete host
3. allow one host in maintance mode in a cluster instead of in a pod
status 6363: resolved fixed