client/lxd/instances: Adds custom name restore support to CreateInstanceFromBackup
client/lxd/instances: Adds custom name restore support to CreateInstanceFromBackup

Utilising a new `X-LXD-name` header.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,atxwebs/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,atxwebs/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,atxwebs/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd