Summary:
`static/index.js` is called by Electron's main process, it does the setup required to run Flipper. However, some of this setup is electron specific, other is not. This moves all non-Electron specific code into `setup.js` which later can be called from node, too. All Electron specific stuff is still in `static/index.js`.
On a side note, this remove the renaming from `.sonar` to `.flipper` config folder, as I think most users should have been migrated by now, users that are not yet migrated will lose their settings, which isn't too much of an issue as our settings are very minimal anyways.
Reviewed By: passy
Differential Revision: D13638253
fbshipit-source-id: 22ab2a65ffec87b40bd86899630d582d9dc5d05c
