Add ESS debian mirror in Dockerfile

JIRA INFRA-6350

Dockerfile

 FROM python:3.8-slim as base
 
+# Add ESS specific debian repository mirror
+RUN echo "deb https://artifactory.esss.lu.se/artifactory/debian-mirror stable main" | tee /etc/apt/sources.list.d/ess-debian-mirror.list
+
 # Install Python dependencies in an intermediate image
 # as some requires a compiler (psycopg2)
 FROM base as builder
@@ -65,6 +68,8 @@ RUN apt-get update \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/*
 
+RUN rm /etc/apt/sources.list.d/ess-debian-mirror.list
+
 COPY --chown=csi:csi . /app/
 WORKDIR /app
 RUN echo "__version__ = \"$(git describe)\"" > app/_version.py