Add Flipper support for Loop app

[aforcier]

(Stacked on top of #470 to prevent a conflict since I renamed the app in that PR.)

Adds support for Flipper, a runtime debugging tool, to the example app in debug.

(You've probably used Stetho in FluxC or WPAndroid - Flipper is a replacement for Stetho, and comes with a Mac binary as a debugging tool. There's an open PR in FluxC introducing Flipper there.)

I found it useful for being able to inspect layouts in realtime:

There are other features like network interception and storage inspection but those aren't useful for this project, so I just enabled the layout inspector.

To test:

1. Install the desktop app: https://www.facebook.com/fbflipper/public/mac and run it.
2. Run the Loop app.
3. Make sure the Flipper app connects to the device/emulator.
4. Enable the layout inspector in the desktop app.
5. Make sure you can inspect the layout.

More about Flipper here: https://fbflipper.com/

[jd-alexander]

@aforcier Nice addition! I assume this is ready for review now? I would assign to myself and do so 🙏

[aforcier]

Go for it @jd-alexander !

[aforcier]

Also just a note that there's an open issue for adding Flipper to WPAndroid as well: wordpress-mobile/WordPress-Android#11615

Though from a quick try I did a bit ago, it wasn't straightforward. I think there's a dependency conflict between the Flipper libraries and react native but I didn't spend much time on it.

[jd-alexander]

Also just a note that there's an open issue for adding Flipper to WPAndroid as well: wordpress-mobile/WordPress-Android#11615
Though from a quick try I did a bit ago, it wasn't straightforward. I think there's a dependency conflict between the Flipper libraries and react native but I didn't spend much time on it.

Understood. Thanks for the note 🙇

Reviewing this now.

[jd-alexander]

Thanks, @aforcier Tested and it works. I left a minor comment. But apart from that, this is good to go. LGTM 🚢