Fix broken links

.gitlab-ci.yml

config.toml

content/cloud/about/_index.md

content/cloud/advanced-features/index.md

content/cloud/best-practices/index.md

content/cloud/contribute/index.md

content/cloud/faq/index.md

content/cloud/flavors/index.md

content/cloud/network/index.md

content/cloud/quick-start/index.md

content/cloud/register/index.md

content/cloud/tools/index.md

layouts/partials/menu.html