Add support to Keystone Auth for external user linking

Also adds Keystone V3 support

static/directives/config/config-setup-tool.html

@@ -523,6 +523,15 @@
 
         <!--  Keystone Authentication -->
         <table class="config-table" ng-if="config.AUTHENTICATION_TYPE == 'Keystone'">
+          <tr>
+            <td>Keystone API Version:</td>
+            <td>
+              <select ng-model="config.KEYSTONE_AUTH_VERSION">
+                <option value="2">2.0</option>
+                <option value="3">V3</option>
+              </select>
+            </td>
+          </tr>
           <tr>
             <td>Keystone Authentication URL:</td>
             <td>