Deploy Pathora Viewer: components, routes, and tile server (#5)

- Deploy Pathora Viewer: components, routes, and tile server (39a2f28fec1b0d2ea8892191d72dc896e3e88eec)

frontend/src/index.tsx

@@ -1,5 +1,14 @@
-import './index.css';
-import React from "react";
-import { render } from "react-dom";
-import { App } from "./App";
-render(<App />, document.getElementById("root"));
+import './index.css';
+import React from "react";
+import { createRoot } from "react-dom/client";
+import { AppRouter } from "./AppRouter";
+
+let rootElement = document.getElementById("root");
+if (!rootElement) {
+  rootElement = document.createElement("div");
+  rootElement.id = "root";
+  document.body.appendChild(rootElement);
+}
+
+const root = createRoot(rootElement);
+root.render(<AppRouter />);