Add basic content to the composer section

docs/composer/library/composer-json-utils/index.md

docs/composer/library/docker-traefik/index.md

docs/composer/plugin/ahoy/index.md

docs/composer/plugin/b4d/index.md

docs/composer/plugin/d4d/index.md

docs/composer/plugin/d8-sass-theme/index.md

docs/composer/plugin/d8-scaffold/index.md

docs/composer/plugin/d9-scaffold/index.md

docs/composer/plugin/dorgflow/index.md

docs/composer/plugin/drupal-dev-environment/index.md

docs/composer/plugin/drupal-environment/index.md

docs/composer/project/d8/index.md

docs/composer/project/d9/index.md