doc: documented images organisation and refactored code

README.md

docs/Gestions des plans/etang_users.md

docusaurus.config.js

src/components/CarouselLibre.js

src/components/HomepageFeatures.js

src/components/HomepagePromises.js

src/pages/communaute.mdx

src/pages/tarifs.mdx

src/theme/Footer/index.js

static/img/components/CarouselLibre/Ansible_logo.png

static/img/components/CarouselLibre/Terraform_logo.png

static/img/components/CarouselLibre/borg_logo.png

static/img/components/CarouselLibre/debian_logo.png

static/img/components/CarouselLibre/docusaurus.png

static/img/components/CarouselLibre/gitlab_logo.png

static/img/components/CarouselLibre/mattermost_logo.png

static/img/components/CarouselLibre/openlogo-nd.svg

static/img/components/CarouselLibre/restic_logo.png

static/img/components/HomepageFeatures/beer.png

static/img/components/HomepageFeatures/chemistry.svg