Add support to build release containers

Signed-off-by: Tobias Wolf <wolf@b1-systems.de>
On-behalf-of: SAP <tobias.wolf@sap.com>

Author: NotTheEvilOne

.github/workflows/Containerfile

@@ -0,0 +1,18 @@
+FROM ghcr.io/gardenlinux/gardenlinux:2150.1.0 as installer
+
+RUN ["apt-get", "update"]
+RUN ["apt-get", "install", "-y", "ca-certificates", "git", "python3", "python3-pip"]
+RUN ["mkdir", "-p", "/opt/app"]
+RUN ["python3", "-m", "venv", "--system-site-packages", "--without-pip", "/opt/app"]
+RUN ["/opt/app/bin/python", "-m", "pip", "install", "--break-system-packages", "git+https://github.com/gardenlinux/python-gardenlinux-lib.git@0.10.20"]
+
+FROM ghcr.io/gardenlinux/gardenlinux:2150.1.0 as base
+LABEL org.opencontainers.image.source="https://github.com/gardenlinux/python-gardenlinux-lib"
+
+RUN ["apt-get", "update"]
+RUN ["apt-get", "install", "-y", "podman", "python3"]
+
+COPY --from=installer /opt/app /opt/app
+
+WORKDIR /opt/app
+ENTRYPOINT ["/opt/app/bin/gl-oci"]