Merge branch 'master' into 30-clearify-git-cz-keywords

.gitignore

.gitlab-ci.yml

README.md

chapters/about.md

chapters/bug-tracking.md

chapters/build-ci.md

chapters/cessda-decisions.md

chapters/code-quality.md

chapters/deployment-maintenance.md

chapters/documentation.md

chapters/explanatory-notes.md

chapters/intellectual-property.md

chapters/links.md

chapters/onboarding.md

chapters/retirement.md

chapters/software-tests.md

chapters/style-guides.md

chapters/version-control.md

chapters/yaml-header.md

rdd-technical-reference.md