public static void resolveModelIds(Element component, boolean hosted) {
        for (Element config : XML.getChildren(component, "config")) {
            for (Element value : XML.getChildren(config))
                transformModelValue(value, hosted);
        }
    }
Finds any config values of type 'model' below the given config element and
supplies the url attribute of them if a model id is specified and hosted is true
(regardless of whether an url is already specified).

@param component the XML element of any component
config-model/src/main/java/com/yahoo/vespa/model/container/xml/ModelIdResolver.java