docs: relocate website docs

docs/usage/assets/images/all-dead.jpg

docs/usage/assets/images/broken-lockfile.jpg

docs/usage/assets/images/dashboard-install.png

docs/usage/assets/images/dashboard-login.png

docs/usage/assets/images/dashboard-settings.png

docs/usage/assets/images/github-app-choose-repos.png

docs/usage/assets/images/github-app-install.png

docs/usage/assets/images/logo.png

docs/usage/assets/images/onboarding.png

docs/usage/bazel.md

docs/usage/config-presets.md

docs/usage/configuration-options.md

docs/usage/configuration-templates.md

docs/usage/configure-renovate.md

docs/usage/data-security.md

docs/usage/dependency-pinning.md

docs/usage/docker.md

docs/usage/faq.md

docs/usage/golang.md

docs/usage/install-github-app.md