Feature request: multi-panels in Apple App

[Daeraxa]

There was a big project as part of GSoC a few years ago to do exactly this but I think there were some issues that never got resolved and so the changes were reverted.

Joplin Mobile Tablet Layout

Introduction The current Joplin mobile app is designed for mobile phones. On wider screens like tablet devices, a layout that takes advantage of the extra screen space is needed. I plan to take a progressive enhancement approach in my solution. I plan to build on the current mobile layout and make more features show up when the app detects extra screen space. Goals To implement a layout that: Builds on the current mobile layout Uses the extra screen space for new features Looks good Appro…