Rework configuration process

Dynamically loads `config.json` on startup.

Fixes #167, #284, #449, #486

Change-Id: I9efb1079c0c88e6e0272c5fda734a367aa8f84a3

src/index.jsx

@@ -1,9 +1,17 @@
 import React from "react";
 import { createRoot } from "react-dom/client";
-import App from "./App";
 
-createRoot(document.getElementById("root")).render(
-  <React.StrictMode>
-    <App />
-  </React.StrictMode>
-);
+import App from "./App";
+import { AppContext } from "./AppContext";
+
+fetch("config.json")
+  .then(res => res.json())
+  .then(props =>
+    createRoot(document.getElementById("root")).render(
+      <React.StrictMode>
+        <AppContext.Provider value={props}>
+          <App />
+        </AppContext.Provider>
+      </React.StrictMode>
+    )
+  );