Implement basic execution system and UI

This is a rather large commit that includes all of the following:
- React UI with code editor, runtime renderer and input-output panes
- Language providers for a sample language and Brainfuck
- Implementation of code execution in a web worker
- All-at-once unabortable execution of program fully functional

pages/_app.tsx

@@ -0,0 +1,12 @@
+import "../styles/globals.css";
+import "../styles/editor.css";
+import "@blueprintjs/core/lib/css/blueprint.css";
+import "@blueprintjs/icons/lib/css/blueprint-icons.css";
+import "react-mosaic-component/react-mosaic-component.css";
+import type { AppProps } from "next/app";
+
+function MyApp({ Component, pageProps }: AppProps) {
+  return <Component {...pageProps} />;
+}
+
+export default MyApp;