Reorganize Dockerfile to reduce image size

Dockerfile

@@ -1,28 +1,35 @@
+# Based on https://github.com/plone/volto/blob/master/entrypoint.sh
 FROM node:12-stretch-slim
 
-RUN apt-get update && apt-get install -y git
-
 COPY . /opt/frontend/
-RUN chown -R node /opt/frontend/
-RUN rm -rf /opt/frontend/src/addons/*
+
+
+# Update apt packages
+RUN runDeps="openssl ca-certificates patch git" \
+ && apt-get update \
+ && apt-get install -y --no-install-recommends $runDeps \
+ && apt-get clean \
+ && rm -rf /var/lib/apt/lists/* \
+ && chown -R node /opt/frontend/ \
+ && rm -rf /opt/frontend/src/addons/* \
+ && cd /opt/frontend \
+ && npm install -g mrs-developer
 
 WORKDIR /opt/frontend/
-RUN npm install -g mrs-developer
+
 USER node
 
 ARG MAX_OLD_SPACE_SIZE=8192
 ENV NODE_OPTIONS=--max_old_space_size=$MAX_OLD_SPACE_SIZE
 
-RUN cd /opt/frontend
-
-RUN yarn develop
-RUN RAZZLE_API_PATH=VOLTO_API_PATH RAZZLE_INTERNAL_API_PATH=VOLTO_INTERNAL_API_PATH yarn
-
-RUN RAZZLE_API_PATH=VOLTO_API_PATH RAZZLE_INTERNAL_API_PATH=VOLTO_INTERNAL_API_PATH yarn build \
+RUN cd /opt/frontend \
+ && yarn develop \
+ && RAZZLE_API_PATH=VOLTO_API_PATH RAZZLE_INTERNAL_API_PATH=VOLTO_INTERNAL_API_PATH yarn \
+ && RAZZLE_API_PATH=VOLTO_API_PATH RAZZLE_INTERNAL_API_PATH=VOLTO_INTERNAL_API_PATH yarn build \
  && rm -rf /home/node/.cache
 
 EXPOSE 3000 3001 4000 4001
 
 ENTRYPOINT ["/opt/frontend/entrypoint-prod.sh"]
 CMD ["yarn", "start:prod"]
-USER root
+USER root