Move the software RAID code path from grub2-install to
efibootmgr:
- remove the UEFI efibootmgr exception for software RAID
- create and populate the ESPs on the holder disks
- update the NVRAM with all ESPs (the component devices
of the ESP mirror, use unique labels to avoid unintentional
deduplication of entries in the NVRAM)
Story: #2009794
Change-Id: I7ed34e595215194a589c2f1cd0b39ff0336da8f1