diskmanage: add wipe_blockdev method
based on the wipe_disks method from pve-manager's Ceph/Tools.pm with the
following main differences:
* use wipefs to wipe labels first (to avoid sgdisk complaining about the
backed up GPT structure on a subsequent GPT initialization)
* only take one device as an argument
* do not use an absolute path for 'dd'
* die if one of the command fails
The wipefs command makes checks and complains about e.g. mounted or active
devices. One could supply --force to wipefs, but in many such situations it
does not work as expected, because the device would still be detected as in-use
afterwards, and further manaual steps would be needed.
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>