Summary:
Includes the following changes:
* Adds "Click to expand" hover tooltip to all images
* Adds support for minimize/maximize by double clicking tutorial popup header
* Add New menu (and all other popups) should now persist when user moves tutorial popup
* Preserves scrollbar position when minimizing and maximizing tutorial popup
* Formula cell editor (and other elements) should now be stacked under tutorial
Test Plan: Browser and manual tests.
Reviewers: jarek
Reviewed By: jarek
Differential Revision: https://phab.getgrist.com/D3864