Migrate all plugins to spec v2

Summary: All the plugins migrated to spec v2 to allow packaging/publishing them independently from Flipper releases.

Reviewed By: passy

Differential Revision: D22041384

fbshipit-source-id: 23bfaf724f771a57bd628b9ea1c4d37846534a93

desktop/plugins/layout/package.json

@@ -1,7 +1,10 @@
 {
-  "name": "Inspector",
+  "$schema": "https://fbflipper.com/schemas/plugin-package/v2.json",
+  "name": "flipper-plugin-inspector",
+  "id": "Inspector",
   "version": "1.0.0",
-  "main": "index.tsx",
+  "main": "dist/bundle.js",
+  "flipperBundlerEntry": "index.tsx",
   "license": "MIT",
   "keywords": [
     "flipper-plugin"
@@ -18,5 +21,8 @@
   "bugs": {
     "email": "oncall+flipper@xmail.facebook.com",
     "url": "https://fb.workplace.com/groups/flippersupport/"
+  },
+  "scripts": {
+    "prepack": "../../pkg/bin/run bundle"
   }
-}
+}