[Gazpacho] Implement functionality for the is_root_volume RAID config

The is_root_volume config option has been listed in the documentation for a while, but has not been supported by the IPA. With this patch, if there is a logical disk in the target_raid_config with the setting is_root_volume: True, it will be picked up as the root device (root_device hints will not even be checked). Additionally, if is_root_volume: False, for a volume then it will be excluded from the list of possible root devices used by the root_device hints.

Depends-On: https://review.opendev.org/c/openstack/ironic-python-agent/+/965797 Change-Id: If195b8f2c471cd7cf3f690664c7f13b6cef10ce2 Signed-off-by: Jakub Jelinek jakub.jelinek@cern.ch Signed-off-by: Morten Stephansen morten.kaastrup.stephansen@cern.ch (cherry picked from commit 487f069ee63877351ed98c4a903bb1c9bd22576a)