* Add initrd=main karg directive for UEFI (ignored by BIOS)
* Update Butane config version to v1.4.0 (generates Ignition v3.3.0)
in `fedora-coreos` and `fedora-coreos-install` examples
* Update virt-install flag --os-variant
* Removed virt-install deprecated flag --os-type
* Remove virt-install QEMU/KVM event preserve since it apparently
wasn't implemented anyway and QEMU/KVM now warns about it
* Remove serial consol kernel argument from examples, but still
mention it in docs
Rel:
* https://github.com/coreos/fedora-coreos-docs/pull/282
* https://www.spinics.net/linux/fedora/libvir/msg222078.html
* Local QEMU/KVM tutorials use either docker or rkt/acbuild,
but they're dated. rkt and acbuild are no longer in mainstream
use since they successfully drove OCI standardization
* Remove the rkt examples, as they are just more difficult for
newcomers to use and seldom maintained at this point
* Retain Docker examples, although podman will likely supplant
all docker usage in future
* Change assets download location to examples/assets
* FileStore should default to /var/lib/bootcfg/{profiles,groups,
ignition,cloud}
* Assets location should default to /var/lib/bootcfg/assets
* Fix -rpcAddress flag to be -rpc-address
