KEYCLOAK-3092: Show 20 users per page in user list by default

More sensible default for number of users shown per page in
the user listing of the admin console.
This is also recommended in the patternfly guidelines.

Prior to the PR only 5 users were shown per page.

themes/src/main/resources/theme/base/admin/resources/js/controllers/users.js

@@ -246,9 +246,9 @@ module.controller('UserListCtrl', function($scope, realm, User, UserImpersonatio
 
     $scope.query = {
         realm: realm.realm,
-        max : 5,
+        max : 20,
         first : 0
-    }
+    };
 
     $scope.impersonate = function(userId) {
         UserImpersonation.save({realm : realm.realm, user: userId}, function (data) {