Update WebDAV add-on section

[knstvk]

[Shade30]

Also clarify the following info regarding HTTPS Configuration:

The <base-package> in the path to the keystore (server.ssl.key-store property) should be presented as a slash-separated path: server.ssl.key-store = classpath:com/example/demo/keystore/localhost.jks

Also the URL in printApplicationUrl() method in the application class should be changed to https:// after configuring HTTPS:

    @EventListener
    public void printApplicationUrl(final ApplicationStartedEvent event) {
        LoggerFactory.getLogger(DemoApplication.class).info("Application started at "
                + "https://localhost:"
                + environment.getProperty("local.server.port")
                + Strings.nullToEmpty(environment.getProperty("server.servlet.context-path")));
    }