Summary:
New icon to expand an active section and show it as a popup (just like raw data views).
"Show raw data" popup couldn't be reused (as it is basically a different page), so now
we have two kinds of popups that look the same.
1. Raw data popup - to show an alien section on a page (a section from a different view). This is used by "Show raw data" button, it is basically a different page that shows an arbitrary section.
2. Layout popup - a popup generated by Layout.ts that basically hides every other section and adds an overlay effect to itself.
Other changes
- Layout.js was migrated to typescript
- "Show raw data" menu item was converted to link
Test Plan: new tests
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3764
