Add ubuntu impish to libvirt images

Nova requires libvirt 7.0+ in the xena release and focal only
has 6.X. This change adds in an ubuntu impish image option for
libvirt to handle xena.

A future change should remove this and migrate libvirt to use
jammy.

Change-Id: Ie162df7ceecb69a8abc47280a63643e0ee0d175f

libvirt/Dockerfile.ubuntu_impish

@@ -0,0 +1,24 @@
+ARG FROM=docker.io/ubuntu:impish
+FROM ${FROM}
+
+ARG UBUNTU_RELEASE=focal
+ARG CEPH_RELEASE=octopus
+ARG CEPH_RELEASE_TAG=""
+ARG PROJECT=nova
+ARG UID=42424
+ARG GID=42424
+
+ARG CEPH_REPO=http://download.ceph.com/debian-${CEPH_RELEASE}/
+ARG CEPH_KEY=http://download.ceph.com/keys/release.asc
+
+ADD ${CEPH_KEY} /etc/apt/ceph-${CEPH_RELEASE}.key
+COPY ./ubuntu-install-libvirt.sh /tmp/ubuntu-install-libvirt.sh
+RUN set -ex ;\
+    export DEBIAN_FRONTEND=noninteractive ;\
+    apt-get update ;\
+    apt-get install --no-install-recommends -y \
+      apt-transport-https \
+      ca-certificates \
+      gnupg ;\
+    /tmp/ubuntu-install-libvirt.sh ;\
+    rm -rf /tmp/*

zuul.d/libvirt.yaml

@@ -68,6 +68,13 @@
           tags:
             - latest-ubuntu_focal
             - "ubuntu_focal-{{ currentdate }}"
+        # NOTE(gagehugo): Once jammy is released, use that and delete impish
+        - context: libvirt
+          repository: openstackhelm/libvirt
+          dockerfile: Dockerfile.ubuntu_impish
+          tags:
+            - latest-ubuntu_impish
+            - "ubuntu_impish-{{ currentdate }}"
     files: &libvirt_files
       - libvirt/.*
       - zuul.d/libvirt.yaml