Propose: enable vyos cloud-init to have the same disk_setup and mount functionality as upstream cloud-init project, let vyos cloud-init able to setup additional disk(partition tables and filesystems), and mount the additional disk when boot.
Action to take: add disk_setup and mounts under cloud_init_modules in https://github.com/vyos/vyos-cloud-init/blob/current/config/cloud.cfg.d/10_vyos.cfg#L16