Introduce container_registry for image prefix

Change-Id: I80067f53aa2b63286b654fff782f0f7b65a2d050
diff --git a/images/nova/Dockerfile b/images/nova/Dockerfile
index 6ad288a..1ce9eb0 100644
--- a/images/nova/Dockerfile
+++ b/images/nova/Dockerfile
@@ -1,9 +1,10 @@
 # SPDX-License-Identifier: Apache-2.0
 # Atmosphere-Rebuild-Time: 2024-12-17T01:27:44Z
 
+ARG REGISTRY
 ARG RELEASE
 
-FROM harbor.atmosphere.dev/library/openstack-venv-builder:${RELEASE} AS build
+FROM ${REGISTRY}/openstack-venv-builder:${RELEASE} AS build
 ARG NOVA_GIT_REF=c199becf52267ba37c5191f6f82e29bb5232b607
 ADD --keep-git-dir=true https://opendev.org/openstack/nova.git#${NOVA_GIT_REF} /src/nova
 RUN git -C /src/nova fetch --unshallow
@@ -25,7 +26,7 @@
     https://github.com/storpool/storpool-openstack-integration/raw/master/drivers/os_brick/openstack/bobcat/storpool.py \
     /var/lib/openstack/lib/python3.10/site-packages/os_brick/initiator/connectors/storpool.py
 
-FROM harbor.atmosphere.dev/library/openstack-python-runtime:${RELEASE}
+FROM ${REGISTRY}/openstack-python-runtime:${RELEASE}
 ADD https://github.com/novnc/noVNC.git#v1.4.0 /usr/share/novnc
 RUN <<EOF bash -xe
 apt-get update -qq