Add buildroot utils/check-package check to the pr-checks.yml workflow.
It checks for common errors/mistakes when creating own buildroot
packages. Also fixed all warnings this utility output for our existing packages.
The proposed changed is to run the qemu guest agent for QEMU hypervisor. QEMU hypervisor and KVM hypervisor are using the same guest agent.
systemd allow detecting the difference between the two hypervisors. The change is using OR trigger, meaning it will trigger if one of the "ConditionVirtualization" rules is true.
