Improve 'forward' code

Move Forwarded into forward.packet and remove deprecated methods. Also
make fields final.

Improve ForwardedProvider:
- use INSTANCE of DelayInformationProvider
- use loop label
- don't throw exceptions in certain cases, instead log

smack-extensions/src/main/java/org/jivesoftware/smackx/delay/provider/DelayInformationProvider.java

@@ -28,6 +28,8 @@ import org.jxmpp.util.XmppDateTime;
  */
 public class DelayInformationProvider extends AbstractDelayInformationProvider {
 
+    public static final DelayInformationProvider INSTANCE = new DelayInformationProvider();
+
     @Override
     protected Date parseDate(String string) throws ParseException {
         return XmppDateTime.parseXEP0082Date(string);