Almost all the virt-who users or customers are used to configure hypervisor's options in /etc/virt-who.d/xxx.conf.
Remove the hypervisor's configuration from /etc/sysconfig/virt-who, will make virt-who easier to use and understand
QE will test this feature in virt-who-0.23.4-1.el8
Blocker rationale: This removal of configuration via environment variable has been in 8.0 for some time. This BZ's purpose is to have a marker for customers.