[DOCS] Added older release notice. (#1401)

Author: debadair

docs/src/reference/asciidoc/page_header.html

@@ -0,0 +1,5 @@
+<p>
+  <strong>NOTE</strong>: You are looking at documentation for an older release. 
+  For the latest information, see the 
+  <a href="../current/index.html">current release documentation</a>. 
+</p>