(core) Expanding widgets

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

app/client/components/BaseView.js

@@ -243,8 +243,6 @@ BaseView.commonCommands = {
 
   copyLink: function() { this.copyLink().catch(reportError); },
 
-  showRawData: function() { this.showRawData().catch(reportError); },
-
   deleteRecords: function(source) { this.deleteRecords(source); },
 
   filterByThisCellValue: function() { this.filterByThisCellValue(); },
@@ -401,13 +399,6 @@ BaseView.prototype.copyLink = async function() {
   }
 };
 
-BaseView.prototype.showRawData = async function() {
-  const sectionId = this.schemaModel.rawViewSectionRef.peek();
-  const anchorUrlState = this.getAnchorLinkForSection(sectionId);
-  anchorUrlState.hash.popup = true;
-  await urlState().pushUrl(anchorUrlState, {replace: true, avoidReload: true});
-}
-
 BaseView.prototype.filterByThisCellValue = function() {
   const rowId = this.viewData.getRowId(this.cursor.rowIndex());
   const col = this.viewSection.viewFields().peek()[this.cursor.fieldIndex()].column();