Added dynamically generated sitemap and robots.txt file to prevent crawling of inline version

src/web/static/robots.txt

@@ -0,0 +1,4 @@
+user-agent: *
+disallow: /cyberchef.htm
+
+sitemap: https://gchq.github.io/CyberChef/sitemap.xml

src/web/static/sitemap.js

@@ -0,0 +1,33 @@
+import sm from "sitemap";
+import OperationConfig from "../../core/config/MetaConfig.js";
+
+
+/**
+ * Generates an XML sitemap for all CyberChef operations and a number of recipes.
+ *
+ * @author n1474335 [n1474335@gmail.com]
+ * @copyright Crown Copyright 2018
+ * @license Apache-2.0
+ */
+
+const sitemap = sm.createSitemap({
+    hostname: "https://gchq.github.io/CyberChef",
+});
+
+sitemap.add({
+    url: "/",
+    changefreq: "weekly",
+    priority: 1.0
+});
+
+for (let op in OperationConfig) {
+    sitemap.add({
+        url: `/op=${encodeURIComponent(op)}`,
+        changeFreq: "yearly",
+        priority: 0.5
+    });
+}
+
+const xml = sitemap.toString();
+
+console.log(xml); // eslint-disable-line no-console