[PROD-16118] Adding feature to control user/group

Change allows to set user and group for QEMU processes run by the system instance
And specify whether libvirt should dynamically change file ownership to match the
Configured user/group above
Related-Prod: PROD-16118

Change-Id: I700f7cd373fffea82a0b1c3b0e22bfd9b2ef3a48
4 files changed