Register zpools as resources.
CLI update:

* Add generic machinery for converting various types from/to string
* Clean up printing ASCII tables
* Add "blocking mode" where progress bar is displayed when submitting a task. Blocks until task completes (or fails)
* Add commands for displaying volume topology and member disks status
* Start working on datasets namespac
* Finally install disks plugin
Add support for getting vdev status, fix raidz vdev creation.
Fix resource IDs
Fix subtasks management, save task exception info to the DB if task fails.
Add support for destroying datasets.
Use correct event name.