Install java for spark and R-datascience images (for packages like RJDemetra)

[odysseu]

Changes:

• few typos in README
• moved the java installation into a separate script for visibility and added the conf necessary for R for when necessary
• added libbz2-dev which is necessary for compiling with jdk for certain R packages like RJDemetra and rJava

NB:

To dev this job, since at this time all scripts are copied during the build of the base image, I temporary added this bit in the concerned dockerfiles :

# temporary to POC instal-java.sh
COPY scripts/ /opt/
RUN chmod -R +x /opt/

and it worked ✅ (see this github action) then I took it back off;

voir screen de la github action