* Update Fedora CoreOS live PXE and disk install examples to
Fedora 33
* Increase libvirt VM memory from 2GB to 3GB to support live
PXE example, which is mostly just for laptop examples/demos.
Reduce the VM count from 3 to 2 to compensate.
* Change `fedora-coreos.ign` to suggest using an ed25519 SSH
key since Fedora CoreOS 33 disables RSA SHA1 (256 is still ok
but most people won't know which they have)
* Refactor examples to boot provision minimal hosts
with Fedora CoreOS or Flatcar Linux
* Remove the etcd3 cluster example or other specific
kinds of hosts
* Update script get-fedora-coreos
* Remove script get-coreos
* 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
In virt-install v1.4.2, the meaning of `--pxe` changed from "allow pxe
boot" to "always pxe boot." This breaks matchbox, since we expect hosts
to pxe-boot only with empty hds. On hosts with v1.4.2, the VMs loop,
re-installing CL over and over.
The flag isn't necessary anyways, since we pass `--boot=hd,network`,
which enables pxe-booting.
* Add `scripts/libvirt create` subcommand for rkt setups
* Add --os-variant=generic to remove nag messages to specify
* Rename places QEMU/KVM VMs were called libvirt VMs
* 4GB disk is too small and routinely fails in libvirt
* Depending on build env, dnsmasq ACI can have an old /etc/resolv.conf
DNS entry embedded. Can rebuild to fix, but use --dns=8.8.8.8 too
* Fix issue where etcd_proxy profile failed to pull metadata
so etcd_proxy wasn't configured after CoreOS install
