feat(rn,build) drop confusing commands

We don't recommend using the RN CLI due to the changes we make to the
standard RN project layout. Xcode and Android Studio should be used to
compile the app instead.

package.json

@@ -177,8 +177,6 @@
     "lint-fix": "eslint  --max-warnings 0 --fix .",
     "postinstall": "patch-package && jetify",
     "validate": "npm ls",
-    "start": "make dev",
-    "ios": "react-native run-ios",
-    "android": "react-native run-android"
+    "start": "make dev"
   }
 }