v2.9.0
docs: Add Jekyll and theme config
docs: make storage.filesystems.path field optional
config: add specs newer than 3.0 to TestConfigStructure
docs: stabilize spec
docs: Add ToC for some long pages
docs: Add index page inspired from README
docs/migrating-configs: spell out Google Cloud Storage
docs/*: add resize partition info
docs: Add Jekyll front matter for existing pages