lxd/storage/drivers/volume: Create bucket local storage volumes using same permissions as custom volumes
lxd/storage/drivers/volume: Create bucket local storage volumes using same permissions as custom volumes

Allows running MinIO process as unprivileged user (as it allows the user to change into volume directory).

The actual `minio` data directory will still use 0700 perms to prevent access by other users.

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

lxc/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,stgraber/lxd