devices: add new disk-{char,block} format
devices: add new disk-{char,block} format

The new device creation format encodes the device name into the device file:

/var/lib/lxd/devices/<container-name>/disk.<device name>.<container path>

Signed-off-by: Christian Brauner <48455ab3070520a2d174545c7239d6d0fabd9a83@ubuntu.com>

lxc/lxd,mjeanson/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,lxc/lxd,pcdummy/lxd,hallyn/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,atxwebs/lxd,Skarlso/lxd,jsavikko/lxd,stgraber/lxd,erikmack/lxd,erikmack/lxd,lxc/lxd,erikmack/lxd,stgraber/lxd,atxwebs/lxd,stgraber/lxd,jsavikko/lxd,mjeanson/lxd,hallyn/lxd,Skarlso/lxd,jsavikko/lxd,Skarlso/lxd,stgraber/lxd,hallyn/lxd,mjeanson/lxd,Skarlso/lxd,stgraber/lxd,lxc/lxd,atxwebs/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,pcdummy/lxd,pcdummy/lxd