WW-4754 Marks sitegraph plugin as deprecated

plugins/sitegraph/pom.xml

@@ -31,7 +31,7 @@
 
     <artifactId>struts2-sitegraph-plugin</artifactId>
     <packaging>jar</packaging>
-    <name>Struts 2 Sitegraph Plugin</name>
+    <name>DEPRECATED: Struts 2 Sitegraph Plugin</name>
 
     <build>
         <plugins>

plugins/sitegraph/src/main/java/org/apache/struts2/Main.java

@@ -44,7 +44,9 @@ import java.util.List;
  * <p>You can access the help information for these tools by simply running the jar without any arguments.</p>
  *
  * <!-- END SNIPPET: javadoc -->
+ * @deprecated
  */
+@Deprecated
 public class Main {
     public static void main(String[] args) {
         if (args.length == 0) {