@StandardException feature working draft

* move feature under experimental
* replace ProviderFor with Provides
* add doc material (to be completed)
* add author

website/usageExamples/StandardExceptionExample_pre.jpage

@@ -0,0 +1,5 @@
+import lombok.experimental.StandardException;
+
+@StandardException
+public class ExampleException extends Exception {
+}