Move desktop-related code to "desktop" subfolder (#872)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/872
Move all the JS code related to desktop app to "desktop" subfolder.

The structure of "desktop" folder:
- `src` - JS code of Flipper desktop app executing in Electron Renderer (Chrome) process. This folder also contains all the Flipper plugins in subfolder "src/plugins".
- `static` - JS code of Flipper desktop app bootstrapping executing in Electron Main (Node.js) process
- `pkg` - Flipper packaging lib and CLI tool
- `doctor` - Flipper diagnostics lib and CLI tool
- `scripts` - Build scripts for Flipper desktop app
- `headless` - Headless version of Flipper app
- `headless-tests` - Integration tests running agains Flipper headless version

Reviewed By: passy

Differential Revision: D20249304

fbshipit-source-id: 9a51c63b51b92b758a02fc8ebf7d3d116770efe9

desktop/static/setup.ts

@@ -0,0 +1,63 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import path from 'path';
+import os from 'os';
+import fs from 'fs';
+
+export type Config = {
+  pluginPaths?: string[];
+  disabledPlugins?: string[];
+  lastWindowPosition?: {
+    x: number;
+    y: number;
+    width: number;
+    height: number;
+  };
+  updater?: boolean | undefined;
+  launcherMsg?: string | undefined;
+  updaterEnabled?: boolean;
+  launcherEnabled?: boolean;
+};
+
+export default function setup(argv: any) {
+  // ensure .flipper folder and config exist
+  const flipperDir = path.join(os.homedir(), '.flipper');
+  if (!fs.existsSync(flipperDir)) {
+    fs.mkdirSync(flipperDir);
+  }
+
+  const configPath = path.join(flipperDir, 'config.json');
+  let config: Config = {
+    pluginPaths: [],
+    disabledPlugins: [],
+  };
+
+  try {
+    config = {
+      ...config,
+      ...JSON.parse(fs.readFileSync(configPath).toString()),
+    };
+  } catch (e) {
+    // file not readable or not parsable, overwrite it with the new config
+    console.warn(`Failed to read ${configPath}: ${e}`);
+    console.info('Writing new default config.');
+    fs.writeFileSync(configPath, JSON.stringify(config));
+  }
+
+  // Non-persistent CLI arguments.
+  config = {
+    ...config,
+    updaterEnabled: argv.updater,
+    launcherEnabled: argv.launcher,
+    launcherMsg: argv.launcherMsg,
+  };
+
+  return {config, configPath, flipperDir};
+}