docs: Client side redirects (one POC) (#10898)

* one simple redirect, as a test

* adding license to header

docs/gatsby-node.js

@@ -0,0 +1,27 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+exports.createPages = ({ actions }) => {
+  const { createRedirect } = actions; //actions is collection of many actions - https://www.gatsbyjs.org/docs/actions
+  createRedirect({
+    fromPath: '/installation.html',
+    toPath: '/docs/installation/installing-superset-using-docker-compose',
+    isPermanent: true,
+  });
+};