This commit enableds strict settings validation on node startup. All settings
passed to elasticsearch either through system properties, yaml files or any other
way to pass settings must be registered and valid. Settings that are unknown ie. due to
typos or due to deprecation or removal will cause the node to NOT start up. Plugins
have to declare all their settings on the `SettingsModule#registerSetting` and settings for
plugins that are not installed must be removed.
This commit also removes the ability to specify the nodes name via `-Des.name` or just `name` in the
configuration files. The node name must be prefixed with the node prexif like `node.name: Boom`. Left over
usage of `name` will also cause startup to fail.
818a9eefb2