Add redirect for /aad to /?feature.enableAadDataPlane=true (#1649)

web.config

@@ -6,6 +6,15 @@
       <mimeMap fileExtension="woff" mimeType="application/font-woff" />
     </staticContent>
     <rewrite>
+      <rules>
+        <rule name="AAD-Redirect" stopProcessing="true">
+          <match url="^aad" ignoreCase="true"/>
+          <conditions>
+            <add input="{HTTP_HOST}" pattern="^cosmos.azure.com" />
+          </conditions>
+          <action type="Redirect" url="/?feature.enableAadDataPlane=true" redirectType="Permanent" />
+        </rule>
+      </rules>
       <outboundRules>
         <rule name="Strict-Transport-Security" enabled="true">
           <match serverVariable="RESPONSE_Strict_Transport_Security" pattern=".*" />