adds a new class (intended to be used under nodes in pve-manager)
which adds the three api calls: list, smart and init
list being a general list of the available disk with infos
smart being a call to get the smart data from a given device
init being a call to write a gpt header to an unused disk
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>