To reduce size of the hardware module and separate the raid specific
code in raid_utils, we move some functions and adapt the tests.
Change-Id: I73f6cf118575b627e66727d88d5567377c1999a0
This change adds support for the physical_disks RAID parameter in
a form of device hints (same as for root device selection).
Change-Id: I9751ab0f86ada41e3b668670dc112d58093b8099
Story: #2006369
Task: #39080