added a skeleton Dockerfile

Dockerfile

+FROM python:3.11
+
+ARG ARTIFACT_VERSION
+
+RUN pip install \
+    --pre \
+    --extra-index-url https://artifactory.software.geant.org/artifactory/api/pypi/geant-swd-pypi/simple \
+    geant-service-orchestrator==${ARTIFACT_VERSION}
+
+CMD ["tail", "-f", "/dev/null"]