Feature request: support for raw.qemu.conf

[WereCatf]

There already is support for raw.qemu, which allows you to override and/or add to the qemu invocation command-line, but sometimes you need to override and/or add to the devices in the configuration-file that is supplied to qemu as well; FreeBSD 13.1 (and newer?) hog the CPU, unless you prevent qemu from passing a virtio-rng device to the VM, for example, and that can only be done via raw.qemu.conf

Reference: https://linuxcontainers.org/lxd/docs/master/howto/instance_qemu_config/