[MSKINS-167] Add deep anchors to headers

Add anchors to sections header using AnchorJS utility.

The Permalink icon is displayed on Mouse-Over.
This helps on sharing links.

This closes #167
diff --git a/src/main/resources/META-INF/maven/site-macros.vm b/src/main/resources/META-INF/maven/site-macros.vm
index 5f0e3d0..9a79d64 100644
--- a/src/main/resources/META-INF/maven/site-macros.vm
+++ b/src/main/resources/META-INF/maven/site-macros.vm
@@ -792,3 +792,11 @@
 Apache Maven Doxia Site Renderer#if( $doxiaSiteRendererVersion ) $doxiaSiteRendererVersion#end##
 #end
 ##
+##
+#macro( anchorJS )
+<script src="https://cdn.jsdelivr.net/npm/anchor-js/anchor.min.js"></script>
+<script>
+  anchors.add();
+</script>
+#end
+##
diff --git a/src/main/resources/META-INF/maven/site.vm b/src/main/resources/META-INF/maven/site.vm
index bc63222..d62435c 100644
--- a/src/main/resources/META-INF/maven/site.vm
+++ b/src/main/resources/META-INF/maven/site.vm
@@ -293,5 +293,6 @@
       </div>
     </footer>
 #**##piwik()
+#**##anchorJS()
   </body>
 </html>