* Add responsive panels to the single-column layout
* Fixes
* Fix not being able to save the preference
* Fix code style issues
* Set max-height on the compose textarea and add a link to relationship manager
* Move TabsBar rendering logic from CSS to the ColumnsArea component
* Add forceSingleColumn mode
* Add unread notifications counter to tabs bar
* Add toggle to control `forceSingleColumn`
* Increase paddings in mobile layout responsively at large sizes