Yarn workspaces

Summary:
1) moved "sonar/desktop/src" to "sonar/desktop/app/src", so "app" is now a separate package containing the core Flipper app code
2) Configured yarn workspaces with the root in "sonar/desktop": app, static, pkg, doctor, headless-tests. Plugins are not included for now, I plan to do this later.

Reviewed By: jknoxville

Differential Revision: D20535782

fbshipit-source-id: 600b2301960f37c7d72166e0d04eba462bec9fc1

desktop/app/src/dispatcher/pluginManager.tsx

@@ -0,0 +1,26 @@
+/**
+ * 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 {Store} from '../reducers/index';
+import {Logger} from '../fb-interfaces/Logger';
+import {registerInstalledPlugins} from '../reducers/pluginManager';
+import {readInstalledPlugins} from '../utils/pluginManager';
+
+function refreshInstalledPlugins(store: Store) {
+  readInstalledPlugins().then(plugins =>
+    store.dispatch(registerInstalledPlugins(plugins)),
+  );
+}
+
+export default (store: Store, _logger: Logger) => {
+  // This needn't happen immediately and is (light) I/O work.
+  window.requestIdleCallback(() => {
+    refreshInstalledPlugins(store);
+  });
+};