add disk hotplug to upstream config

[sathnaga]

add disk hotplug to upstream config

[mopsfelder]

@sathnaga: We may want to mix and match different options like:

• physical and logical block sizes;
• disk types (e.g.: file, block, dir, volume, nvme);
• driver (e.g.: raw, qcow2); and
• cache options (e.g.: none, writethrough, writeback).