support user defined device plugins

Summary:
* move CPU and Logs plugin to plugins directory, set up package.json for them
* adjust plugins/index.js to expose device and client plugins in the same place, adding two new exports

Reviewed By: danielbuechele

Differential Revision: D10247606

fbshipit-source-id: 347bf8b3f9629987ad29d1d2ed025e0c88b9c967

src/MenuBar.js

@@ -7,7 +7,6 @@
 
 import type {FlipperBasePlugin} from './plugin.js';
 
-import {devicePlugins} from './device-plugins/index.js';
 import plugins from './plugins/index.js';
 import electron from 'electron';
 
@@ -69,7 +68,7 @@ export function setupMenuBar() {
 
   // collect all keyboard actions from all plugins
   const registeredActions: Set<?KeyboardAction> = new Set(
-    [...devicePlugins, ...plugins]
+    plugins
       .map((plugin: Class<FlipperBasePlugin<>>) => plugin.keyboardActions || [])
       .reduce((acc: KeyboardActions, cv) => acc.concat(cv), [])
       .map(