public void getConfig(DocumentrouteselectorpolicyConfig.Builder builder) {
        for (Protocol protocol : protocols) {
            if (protocol instanceof DocumentProtocol) {
                ((DocumentProtocol)protocol).getConfig(builder);
            }
        }
    }
Derives all routing settings that can be found by inspecting the given plugin container.

@param plugins all initialized plugins of the vespa model
config-model/src/main/java/com/yahoo/vespa/model/routing/Routing.java