Add Fedora 33 image and CI, remove Fedora 31 (EOL) + update docker packages (#7657)

.gitlab-ci/packet.yml

README.md

Vagrantfile

docs/ci.md

roles/container-engine/docker/vars/debian.yml

roles/container-engine/docker/vars/fedora.yml

roles/container-engine/docker/vars/redhat.yml

roles/container-engine/docker/vars/ubuntu.yml

roles/kubernetes/node/vars/fedora-34.yml

...fra/image-builder/roles/kubevirt-images/defaults/main.yml

tests/cloud_playbooks/roles/packet-ci/defaults/main.yml

tests/files/packet_fedora34-kube-ovn-containerd.yml

tests/files/packet_fedora34-weave.yml