setup webserver for flipper-server

Summary:
This sets up the metro bundler for flipper-server, to be able to serve the front end.

Note that this is a setup that is only relevant for development purposes

Done in this diff:

* setup metro
* setup fast refresh
* setup nodemon to be able to refresh on server changes

Not done in this diff

* Setup FlipperServerImpl in the flipper-server
* Load flipper-ui-core in flipper-ui-browser
* Load plugins
* Support options, env vars etc etc
* Make flipper-server stand alone (it is largely self contained, but still requires some static resources like theming)

Reviewed By: passy, aigoncharov

Differential Revision: D32626137

fbshipit-source-id: 47f580356ddf0993392d3b583082b187661727e9

desktop/flipper-server/src/index.tsx

@@ -7,6 +7,13 @@
  * @format
  */
 
-export function helloWorld() {
-  return true;
-}
+// TODO: currently flipper-server is only suitable for development,
+// needs to be come independently runnable, prebundled, distributed, etc!
+// in future require conditionally
+import {startWebServerDev} from './startWebServerDev';
+import chalk from 'chalk';
+
+startWebServerDev().catch((e) => {
+  console.error(chalk.red('Server error: '), e);
+  process.exit(1);
+});