Merge branch 'readme' into 'main'

.idea/.gitignore

.idea/compiler.xml

.idea/encodings.xml

.idea/jarRepositories.xml

.idea/java-angular.iml

.idea/misc.xml

.idea/modules.xml

.idea/vcs.xml

HELP/GIT-CHEATSHEET.md

HELP/Raccourcis-Intellij.md

HELP/TROUBLESHOOTING.md

README.md

back-skeleton/.env

back-skeleton/.idea/.gitignore

back-skeleton/.idea/compiler.xml

back-skeleton/.idea/encodings.xml

back-skeleton/.idea/jarRepositories.xml

back-skeleton/.idea/misc.xml

back-skeleton/.idea/vcs.xml

back-skeleton/target/classes/application.properties