docker: include .gitignore into .dockerignore

This is to prevent the result of previous in place builds to interfere with the docker image build.

requested review from @c-geek

changed milestone to %1.9

Je ne me rends pas bien compte de l'impact, je n'ai pas les builds en tête. Il faudrait tester la production d'un livrable sur la base de ce commit.

approved this merge request

added 37 commits

• 995da6c3...a5b302a4 - 36 commits from branch dev
• 551f585b - docker: include .gitignore into .dockerignore

Compare with previous version

resolved all threads

mentioned in commit e87912d8

merged