Fixes ``redfish`` RAID interface workflow to not create more than 1
logical disks per controller at the same time when controller does not
support 'Immediate' application time and system needs rebooting.
With this fix virtual disks are grouped by controller and executed
in batches when reboot is required.
This enables ``redfish`` RAID interface to be used with iDRAC systems
directly as although there are many controllers that support 'Immediate'
application time, they do it only when system has completed loading.
System intermittently completes loading after IPA starts executing
clean or deploy steps rendering controllers not supporting 'Immediate'
apply time and requiring reboot. This fix handles such scenario
instead of failing to create more than 1 virtual disk.
Story: 2009863
Task: 44529
Change-Id: Ia2ce34f09695731b0f48798f662006c4904e2223
d7d8f8754b