docs: add banner with link to new reference documentation

DOCSP-9967

Author: Chris Cho

docs/reference/config.toml

@@ -1,9 +1,12 @@
-baseurl = "/node-mongodb-native/steverenaker/DOCS-8756"
+baseurl = "/node-mongodb-native/3.6"
 languageCode = "en-us"
 title = "MongoDB Node.js Driver"
 theme = "mongodb"
 canonifyurls = false
 
+[params]
+    referenceDocsUrl = "https://docs.mongodb.com/drivers/node"
+
 [blackfriday]
   plainIdAnchors = true
 

docs/reference/layouts/partials/header.html

@@ -25,3 +25,5 @@
               <div class="documentwrapper">
                 <div class="bodywrapper">
                   <div class="body">
+
+                    {{ partial "new_version.html" . }}

docs/reference/layouts/partials/new_version.html

@@ -0,0 +1,4 @@
+<div class="alert alert-info" role="alert">
+  Note: You are currently viewing version 3.6 of the Node.js driver documentation.
+  <a href="{{.Site.Params.ReferenceDocsUrl}}">Click here</a> for the latest version.
+</div>