Refactoring of the BuildServer scripts, adding the beta indication in hte GUI

.gitignore

.gitlab-ci.yml

BuildServer/.gitignore

BuildServer/Darwin/.gitignore

BuildServer/Darwin/Scripts/run_build.sh

BuildServer/Darwin/Scripts/run_tests.sh

BuildServer/Darwin/Tools/create-dmg/.gitignore

BuildServer/Debian/run_build.sh

BuildServer/Debian/run_tests.sh

BuildServer/Unix/Debian_resources/DEBIAN/control

BuildServer/Unix/Debian_resources/DEBIAN/copyright

BuildServer/Unix/Debian_resources/MDANSE.desktop

BuildServer/Unix/MacOS_resources/build.py

BuildServer/Unix/MacOS_resources/change_dylib_path.sh

BuildServer/Unix/MacOS_resources/dmg/LICENSE

BuildServer/Unix/MacOS_resources/dmg/README.md

...erver/Unix/MacOS_resources/dmg/builder/create-dmg.builder

BuildServer/Unix/MacOS_resources/dmg/create-dmg

BuildServer/Unix/MacOS_resources/dmg/dmg_background.jpg

BuildServer/Unix/MacOS_resources/dmg/sample