For the values "default", "on", "off"

Replaces
virDeviceAddressPCIMulti
virDomainFeatureState
virDomainIoEventFd
virDomainVirtioEventIdx
virDomainDiskCopyOnRead
virDomainMemDump
virDomainPCIRombarMode
virDomainGraphicsSpicePlaybackCompression