* Migrate from the internal Drone server using a GitHub Workflow
to perform the multi-arch container image build
* Use self-hosted GitHub runners on ARM64 to perform the ARM64
build step faster that QEMU/KVM emulation
* Mandate approval for all workflow runs from outside contributors
since the builds use push credentials and partially run internally
* rkt achieved its mission creating the OCI standard,
pluggable runtimes, and prevented Docker world
domination. We can now proceed with disarmament
* Few, if any, developers still use rkt locally
* Add ipxe.efi to dnsmasq image's /var/lib/tftpboot directory
* Add initrd kernel argument respected only by UEFI
https://github.com/coreos/bugs/issues/1239
* Improve network-setup docs and scripts to cover UEFI clients
and to support launching UEFI QEMU/KVM clusters locally
* Reduce references to grub.efi flow, its not a happy path
* Add grub.efi to get-tftp-files script. This matches prior
dnsmasq images, but was not part of a repeatable build
* Switch rkt run examples to pull from quay.io
* Remove script using acbuild to create ACIs
