public static void writeAppConfig(final AppConfig appConfig, final Path path) throws IOException {
        final DummyConfig config = new DummyConfig(appConfig);
        final ObjectMapper mapper = YamlUtil.getVanillaObjectMapper();
        mapper.writeValue(path.toFile(), config);
    }
Writes {@link AppConfig} to the file as if appConfig was the only property of a wrapper object.
This is essentially a DropWizard configuration file without the DropWizard bits.
stroom-config/stroom-config-app/src/main/java/stroom/config/app/StroomYamlUtil.java